diff --git a/app/code/Magento/Braintree/view/adminhtml/templates/form/cc.phtml b/app/code/Magento/Braintree/view/adminhtml/templates/form/cc.phtml
index 535a5a852fe70..4c15fffa8189f 100644
--- a/app/code/Magento/Braintree/view/adminhtml/templates/form/cc.phtml
+++ b/app/code/Magento/Braintree/view/adminhtml/templates/form/cc.phtml
@@ -83,7 +83,7 @@ $ccType = $block->getInfoData('cc_type');
                    id="<?= /* @noEscape */ $code ?>_vault"
                    name="payment[is_active_payment_token_enabler]"
                    class="admin__control-checkbox"/>
-            <label class="label" for="<?= /* @noEscape */ $code ?>_vault">
+            <label class="label admin__field-label" for="<?= /* @noEscape */ $code ?>_vault">
                 <span><?= $block->escapeHtml(__('Save for later use.')) ?></span>
             </label>
         </div>
diff --git a/app/code/Magento/Bundle/view/frontend/templates/sales/order/items/renderer.phtml b/app/code/Magento/Bundle/view/frontend/templates/sales/order/items/renderer.phtml
index 063d66edb9e70..74e1c5f874954 100644
--- a/app/code/Magento/Bundle/view/frontend/templates/sales/order/items/renderer.phtml
+++ b/app/code/Magento/Bundle/view/frontend/templates/sales/order/items/renderer.phtml
@@ -7,95 +7,111 @@
 // @codingStandardsIgnoreFile
 
 /** @var $block \Magento\Bundle\Block\Sales\Order\Items\Renderer */
+$parentItem = $block->getItem();
+$items = array_merge([$parentItem], $parentItem->getChildrenItems());
+$index = 0;
+$prevOptionId = '';
 ?>
-<?php $parentItem = $block->getItem() ?>
-<?php $items = array_merge([$parentItem], $parentItem->getChildrenItems()); ?>
-<?php $_index = 0 ?>
 
-<?php $_prevOptionId = '' ?>
+<?php foreach ($items as $item): ?>
 
-<?php foreach ($items as $_item): ?>
-
-    <?php if ($block->getItemOptions() || $parentItem->getDescription() || $this->helper('Magento\GiftMessage\Helper\Message')->isMessagesAllowed('order_item', $parentItem) && $parentItem->getGiftMessageId()): ?>
-        <?php $_showlastRow = true ?>
+    <?php if ($block->getItemOptions()
+        || $parentItem->getDescription()
+        || $this->helper('Magento\GiftMessage\Helper\Message')->isMessagesAllowed('order_item', $parentItem)
+        && $parentItem->getGiftMessageId()): ?>
+        <?php $showLastRow = true; ?>
     <?php else: ?>
-        <?php $_showlastRow = false ?>
+        <?php $showLastRow = false; ?>
     <?php endif; ?>
 
-    <?php if ($_item->getParentItem()): ?>
-        <?php $attributes = $block->getSelectionAttributes($_item) ?>
-        <?php if ($_prevOptionId != $attributes['option_id']): ?>
+    <?php if ($item->getParentItem()): ?>
+        <?php $attributes = $block->getSelectionAttributes($item) ?>
+        <?php if ($prevOptionId != $attributes['option_id']): ?>
             <tr class="options-label">
-                <td class="col label" colspan="5"><?= /* @escapeNotVerified */ $attributes['option_label'] ?></td>
+                <td class="col label" colspan="5"><?= $block->escapeHtml($attributes['option_label']); ?></td>
             </tr>
-            <?php $_prevOptionId = $attributes['option_id'] ?>
+            <?php $prevOptionId = $attributes['option_id'] ?>
         <?php endif; ?>
     <?php endif; ?>
-<tr id="order-item-row-<?= /* @escapeNotVerified */ $_item->getId() ?>" class="<?php if ($_item->getParentItem()): ?>item-options-container<?php else: ?>item-parent<?php endif; ?>"<?php if ($_item->getParentItem()): ?> data-th="<?= /* @escapeNotVerified */ $attributes['option_label'] ?>"<?php endif; ?>>
-    <?php if (!$_item->getParentItem()): ?>
-        <td class="col name" data-th="<?= $block->escapeHtml(__('Product Name')) ?>">
-            <strong class="product name product-item-name"><?= $block->escapeHtml($_item->getName()) ?></strong>
+<tr id="order-item-row-<?= /* @noEscape */ $item->getId() ?>"
+    class="<?php if ($item->getParentItem()): ?>
+        item-options-container
+    <?php else: ?>
+        item-parent
+    <?php endif; ?>"
+    <?php if ($item->getParentItem()): ?>
+        data-th="<?= $block->escapeHtml($attributes['option_label']); ?>"
+    <?php endif; ?>>
+    <?php if (!$item->getParentItem()): ?>
+        <td class="col name" data-th="<?= $block->escapeHtml(__('Product Name')); ?>">
+            <strong class="product name product-item-name"><?= $block->escapeHtml($item->getName()); ?></strong>
         </td>
     <?php else: ?>
-        <td class="col value" data-th="<?= $block->escapeHtml(__('Product Name')) ?>"><?= $block->getValueHtml($_item) ?></td>
+        <td class="col value" data-th="<?= $block->escapeHtml(__('Product Name')); ?>">
+            <?= $block->getValueHtml($item); ?>
+        </td>
     <?php endif; ?>
-    <td class="col sku" data-th="<?= $block->escapeHtml(__('SKU')) ?>"><?= /* @escapeNotVerified */ $block->prepareSku($_item->getSku()) ?></td>
-    <td class="col price" data-th="<?= $block->escapeHtml(__('Price')) ?>">
-        <?php if (!$_item->getParentItem()): ?>
-            <?= $block->getItemPriceHtml() ?>
+    <td class="col sku" data-th="<?= $block->escapeHtml(__('SKU')); ?>">
+        <?= /* @noEscape */ $block->prepareSku($item->getSku()); ?>
+    </td>
+    <td class="col price" data-th="<?= $block->escapeHtml(__('Price')); ?>">
+        <?php if (!$item->getParentItem()): ?>
+            <?= /* @noEscape */ $block->getItemPriceHtml(); ?>
         <?php else: ?>
             &nbsp;
         <?php endif; ?>
     </td>
-    <td class="col qty" data-th="<?= $block->escapeHtml(__('Quantity')) ?>">
+    <td class="col qty" data-th="<?= $block->escapeHtml(__('Quantity')); ?>">
         <?php if (
-        ($_item->getParentItem() && $block->isChildCalculated()) ||
-        (!$_item->getParentItem() && !$block->isChildCalculated()) || ($_item->getQtyShipped() > 0 && $_item->getParentItem() && $block->isShipmentSeparately())):?>
+        ($item->getParentItem() && $block->isChildCalculated()) ||
+        (!$item->getParentItem() && !$block->isChildCalculated()) ||
+        ($item->getQtyShipped() > 0 && $item->getParentItem() && $block->isShipmentSeparately())): ?>
             <ul class="items-qty">
         <?php endif; ?>
-        <?php if (($_item->getParentItem() && $block->isChildCalculated()) ||
-            (!$_item->getParentItem() && !$block->isChildCalculated())): ?>
-            <?php if ($_item->getQtyOrdered() > 0): ?>
+        <?php if (($item->getParentItem() && $block->isChildCalculated()) ||
+            (!$item->getParentItem() && !$block->isChildCalculated())): ?>
+            <?php if ($item->getQtyOrdered() > 0): ?>
                 <li class="item">
-                    <span class="title"><?= /* @escapeNotVerified */ __('Ordered') ?></span>
-                    <span class="content"><?= /* @escapeNotVerified */ $_item->getQtyOrdered()*1 ?></span>
+                    <span class="title"><?= $block->escapeHtml(__('Ordered')); ?></span>
+                    <span class="content"><?= /* @noEscape */ $item->getQtyOrdered() * 1; ?></span>
                 </li>
             <?php endif; ?>
-            <?php if ($_item->getQtyShipped() > 0 && !$block->isShipmentSeparately()): ?>
+            <?php if ($item->getQtyShipped() > 0 && !$block->isShipmentSeparately()): ?>
                 <li class="item">
-                    <span class="title"><?= /* @escapeNotVerified */ __('Shipped') ?></span>
-                    <span class="content"><?= /* @escapeNotVerified */ $_item->getQtyShipped()*1 ?></span>
+                    <span class="title"><?= $block->escapeHtml(__('Shipped')); ?></span>
+                    <span class="content"><?= /* @noEscape */ $item->getQtyShipped() * 1; ?></span>
                 </li>
             <?php endif; ?>
-            <?php if ($_item->getQtyCanceled() > 0): ?>
+            <?php if ($item->getQtyCanceled() > 0): ?>
                 <li class="item">
-                    <span class="title"><?= /* @escapeNotVerified */ __('Canceled') ?></span>
-                    <span class="content"><?= /* @escapeNotVerified */ $_item->getQtyCanceled()*1 ?></span>
+                    <span class="title"><?= $block->escapeHtml(__('Canceled')); ?></span>
+                    <span class="content"><?= /* @noEscape */ $item->getQtyCanceled() * 1; ?></span>
                 </li>
             <?php endif; ?>
-            <?php if ($_item->getQtyRefunded() > 0): ?>
+            <?php if ($item->getQtyRefunded() > 0): ?>
                 <li class="item">
-                    <span class="title"><?= /* @escapeNotVerified */ __('Refunded') ?></span>
-                    <span class="content"><?= /* @escapeNotVerified */ $_item->getQtyRefunded()*1 ?></span>
+                    <span class="title"><?= $block->escapeHtml(__('Refunded')); ?></span>
+                    <span class="content"><?= /* @noEscape */ $item->getQtyRefunded() * 1; ?></span>
                 </li>
             <?php endif; ?>
-        <?php elseif ($_item->getQtyShipped() > 0 && $_item->getParentItem() && $block->isShipmentSeparately()): ?>
+        <?php elseif ($item->getQtyShipped() > 0 && $item->getParentItem() && $block->isShipmentSeparately()): ?>
             <li class="item">
-                <span class="title"><?= /* @escapeNotVerified */ __('Shipped') ?></span>
-                <span class="content"><?= /* @escapeNotVerified */ $_item->getQtyShipped()*1 ?></span>
+                <span class="title"><?= $block->escapeHtml(__('Shipped')); ?></span>
+                <span class="content"><?= /* @noEscape */ $item->getQtyShipped() * 1; ?></span>
             </li>
         <?php else: ?>
-            &nbsp;
+            <span class="content"><?= /* @noEscape */ $parentItem->getQtyOrdered() * 1; ?></span>
         <?php endif; ?>
         <?php if (
-        ($_item->getParentItem() && $block->isChildCalculated()) ||
-        (!$_item->getParentItem() && !$block->isChildCalculated()) || ($_item->getQtyShipped() > 0 && $_item->getParentItem() && $block->isShipmentSeparately())):?>
+        ($item->getParentItem() && $block->isChildCalculated()) ||
+        (!$item->getParentItem() && !$block->isChildCalculated()) ||
+        ($item->getQtyShipped() > 0 && $item->getParentItem() && $block->isShipmentSeparately())):?>
             </ul>
         <?php endif; ?>
     </td>
     <td class="col subtotal" data-th="<?= $block->escapeHtml(__('Subtotal')) ?>">
-        <?php if (!$_item->getParentItem()): ?>
-            <?= $block->getItemRowTotalHtml() ?>
+        <?php if (!$item->getParentItem()): ?>
+            <?= /* @noEscape */ $block->getItemRowTotalHtml(); ?>
         <?php else: ?>
             &nbsp;
         <?php endif; ?>
@@ -103,33 +119,38 @@
 </tr>
 <?php endforeach; ?>
 
-<?php if ($_showlastRow && (($_options = $block->getItemOptions()) || $block->escapeHtml($_item->getDescription()))): ?>
+<?php if ($showLastRow && (($options = $block->getItemOptions()) || $block->escapeHtml($item->getDescription()))): ?>
 <tr>
     <td class="col options" colspan="5">
-        <?php if ($_options = $block->getItemOptions()): ?>
+        <?php if ($options = $block->getItemOptions()): ?>
             <dl class="item-options">
-                <?php foreach ($_options as $_option) : ?>
-                    <dt><?= $block->escapeHtml($_option['label']) ?></dt>
+                <?php foreach ($options as $option) : ?>
+                    <dt><?= $block->escapeHtml($option['label']) ?></dt>
                     <?php if (!$block->getPrintStatus()): ?>
-                        <?php $_formatedOptionValue = $block->getFormatedOptionValue($_option) ?>
-                        <dd<?php if (isset($_formatedOptionValue['full_view'])): ?> class="tooltip wrapper"<?php endif; ?>>
-                            <?= /* @escapeNotVerified */ $_formatedOptionValue['value'] ?>
-                            <?php if (isset($_formatedOptionValue['full_view'])): ?>
+                        <?php $formattedOptionValue = $block->getFormatedOptionValue($option) ?>
+                        <dd<?php if (isset($formattedOptionValue['full_view'])): ?>
+                            class="tooltip wrapper"
+                        <?php endif; ?>>
+                            <?= /* @noEscape */ $formattedOptionValue['value'] ?>
+                            <?php if (isset($formattedOptionValue['full_view'])): ?>
                                 <div class="tooltip content">
                                     <dl class="item options">
-                                        <dt><?= $block->escapeHtml($_option['label']) ?></dt>
-                                        <dd><?= /* @escapeNotVerified */ $_formatedOptionValue['full_view'] ?></dd>
+                                        <dt><?= $block->escapeHtml($option['label']); ?></dt>
+                                        <dd><?= /* @noEscape */ $formattedOptionValue['full_view']; ?></dd>
                                     </dl>
                                 </div>
                             <?php endif; ?>
                         </dd>
                     <?php else: ?>
-                        <dd><?= $block->escapeHtml((isset($_option['print_value']) ? $_option['print_value'] : $_option['value'])) ?></dd>
+                        <dd><?= $block->escapeHtml((isset($option['print_value']) ?
+                                $option['print_value'] :
+                                $option['value'])); ?>
+                        </dd>
                     <?php endif; ?>
                 <?php endforeach; ?>
             </dl>
         <?php endif; ?>
-        <?= $block->escapeHtml($_item->getDescription()) ?>
+        <?= $block->escapeHtml($item->getDescription()); ?>
     </td>
 </tr>
 <?php endif; ?>
diff --git a/app/code/Magento/Catalog/Model/Product.php b/app/code/Magento/Catalog/Model/Product.php
index 8a9233f176c61..831644a553b4b 100644
--- a/app/code/Magento/Catalog/Model/Product.php
+++ b/app/code/Magento/Catalog/Model/Product.php
@@ -714,7 +714,7 @@ public function getIdBySku($sku)
     public function getCategoryId()
     {
         $category = $this->_registry->registry('current_category');
-        if ($category) {
+        if ($category && in_array($category->getId(), $this->getCategoryIds())) {
             return $category->getId();
         }
         return false;
diff --git a/app/code/Magento/Catalog/Model/ResourceModel/Category/RedundantCategoryImageChecker.php b/app/code/Magento/Catalog/Model/ResourceModel/Category/RedundantCategoryImageChecker.php
new file mode 100644
index 0000000000000..b683bcd803bd3
--- /dev/null
+++ b/app/code/Magento/Catalog/Model/ResourceModel/Category/RedundantCategoryImageChecker.php
@@ -0,0 +1,52 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\Catalog\Model\ResourceModel\Category;
+
+use Magento\Catalog\Api\CategoryListInterface;
+use Magento\Framework\Api\SearchCriteriaBuilder;
+
+/**
+ * Check if Image is currently used in any category as Category Image.
+ */
+class RedundantCategoryImageChecker
+{
+    /**
+     * @var SearchCriteriaBuilder
+     */
+    private $searchCriteriaBuilder;
+
+    /**
+     * @var CategoryListInterface
+     */
+    private $categoryList;
+
+    public function __construct(
+        CategoryListInterface $categoryList,
+        SearchCriteriaBuilder $searchCriteriaBuilder
+    ) {
+        $this->categoryList = $categoryList;
+        $this->searchCriteriaBuilder = $searchCriteriaBuilder;
+    }
+
+    /**
+     * Checks if Image is currently used in any category as Category Image.
+     *
+     * Returns true if not.
+     *
+     * @param string $imageName
+     * @return bool
+     */
+    public function execute(string $imageName): bool
+    {
+        /** @var SearchCriteriaBuilder $searchCriteriaBuilder */
+        $searchCriteria = $this->searchCriteriaBuilder->addFilter('image', $imageName)->create();
+        $categories = $this->categoryList->getList($searchCriteria)->getItems();
+
+        return empty($categories);
+    }
+}
diff --git a/app/code/Magento/Catalog/Plugin/Model/ResourceModel/Category/RemoveRedundantImagePlugin.php b/app/code/Magento/Catalog/Plugin/Model/ResourceModel/Category/RemoveRedundantImagePlugin.php
new file mode 100644
index 0000000000000..59f1051b8ed56
--- /dev/null
+++ b/app/code/Magento/Catalog/Plugin/Model/ResourceModel/Category/RemoveRedundantImagePlugin.php
@@ -0,0 +1,77 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\Catalog\Plugin\Model\ResourceModel\Category;
+
+use Magento\Catalog\Model\ImageUploader;
+use Magento\Catalog\Model\ResourceModel\Category as CategoryResource;
+use Magento\Catalog\Model\ResourceModel\Category\RedundantCategoryImageChecker;
+use Magento\Framework\App\Filesystem\DirectoryList;
+use Magento\Framework\Filesystem;
+use Magento\Framework\Model\AbstractModel;
+
+/**
+ * Remove old Category Image file from pub/media/catalog/category directory if such Image is not used anymore.
+ */
+class RemoveRedundantImagePlugin
+{
+    /**
+     * @var Filesystem
+     */
+    private $filesystem;
+
+    /**
+     * @var ImageUploader
+     */
+    private $imageUploader;
+
+    /**
+     * @var RedundantCategoryImageChecker
+     */
+    private $redundantCategoryImageChecker;
+
+    public function __construct(
+        Filesystem $filesystem,
+        ImageUploader $imageUploader,
+        RedundantCategoryImageChecker $redundantCategoryImageChecker
+    ) {
+        $this->filesystem = $filesystem;
+        $this->imageUploader = $imageUploader;
+        $this->redundantCategoryImageChecker = $redundantCategoryImageChecker;
+    }
+
+    /**
+     * Removes Image file if it is not used anymore.
+     *
+     * @param CategoryResource $subject
+     * @param CategoryResource $result
+     * @param AbstractModel $category
+     * @return CategoryResource
+     *
+     * @throws \Magento\Framework\Exception\FileSystemException
+     * @SuppressWarnings(PHPMD.UnusedFormalParameter)
+     */
+    public function afterSave(
+        CategoryResource $subject,
+        CategoryResource $result,
+        AbstractModel $category
+    ): CategoryResource {
+        $originalImage = $category->getOrigData('image');
+        if (null !== $originalImage
+            && $originalImage !== $category->getImage()
+            && $this->redundantCategoryImageChecker->execute($originalImage)
+        ) {
+            $basePath = $this->imageUploader->getBasePath();
+            $baseImagePath = $this->imageUploader->getFilePath($basePath, $originalImage);
+            /** @var \Magento\Framework\Filesystem\Directory\WriteInterface $mediaDirectory */
+            $mediaDirectory = $this->filesystem->getDirectoryWrite(DirectoryList::MEDIA);
+            $mediaDirectory->delete($baseImagePath);
+        }
+
+        return $result;
+    }
+}
diff --git a/app/code/Magento/Catalog/Test/Unit/Model/ProductTest.php b/app/code/Magento/Catalog/Test/Unit/Model/ProductTest.php
index 483283e777118..677a45c41f846 100644
--- a/app/code/Magento/Catalog/Test/Unit/Model/ProductTest.php
+++ b/app/code/Magento/Catalog/Test/Unit/Model/ProductTest.php
@@ -543,6 +543,7 @@ public function testSetCategoryCollection()
 
     public function testGetCategory()
     {
+        $this->model->setData('category_ids', [10]);
         $this->category->expects($this->any())->method('getId')->will($this->returnValue(10));
         $this->registry->expects($this->any())->method('registry')->will($this->returnValue($this->category));
         $this->categoryRepository->expects($this->any())->method('get')->will($this->returnValue($this->category));
@@ -551,7 +552,8 @@ public function testGetCategory()
 
     public function testGetCategoryId()
     {
-        $this->category->expects($this->once())->method('getId')->will($this->returnValue(10));
+        $this->model->setData('category_ids', [10]);
+        $this->category->expects($this->any())->method('getId')->will($this->returnValue(10));
 
         $this->registry->expects($this->at(0))->method('registry');
         $this->registry->expects($this->at(1))->method('registry')->will($this->returnValue($this->category));
@@ -559,6 +561,14 @@ public function testGetCategoryId()
         $this->assertEquals(10, $this->model->getCategoryId());
     }
 
+    public function testGetCategoryIdWhenProductNotInCurrentCategory()
+    {
+        $this->model->setData('category_ids', [12]);
+        $this->category->expects($this->once())->method('getId')->will($this->returnValue(10));
+        $this->registry->expects($this->any())->method('registry')->will($this->returnValue($this->category));
+        $this->assertFalse($this->model->getCategoryId());
+    }
+
     public function testGetIdBySku()
     {
         $this->resource->expects($this->once())->method('getIdBySku')->will($this->returnValue(5));
diff --git a/app/code/Magento/Catalog/etc/di.xml b/app/code/Magento/Catalog/etc/di.xml
index 5b87c7d6ac030..1d3e9a931b677 100644
--- a/app/code/Magento/Catalog/etc/di.xml
+++ b/app/code/Magento/Catalog/etc/di.xml
@@ -907,6 +907,14 @@
     <type name="Magento\Quote\Model\Quote\Item\ToOrderItem">
         <plugin name="copy_quote_files_to_order" type="Magento\Catalog\Model\Plugin\QuoteItemProductOption"/>
     </type>
+    <type name="Magento\Catalog\Model\ResourceModel\Category">
+        <plugin name="remove_redundant_image" type="Magento\Catalog\Plugin\Model\ResourceModel\Category\RemoveRedundantImagePlugin"/>
+    </type>
+    <type name="Magento\Catalog\Plugin\Model\ResourceModel\Category\RemoveRedundantImagePlugin">
+        <arguments>
+            <argument name="imageUploader" xsi:type="object">Magento\Catalog\CategoryImageUpload</argument>
+        </arguments>
+    </type>
     <preference for="Magento\Catalog\Model\ResourceModel\Product\BaseSelectProcessorInterface" type="Magento\Catalog\Model\ResourceModel\Product\CompositeWithWebsiteProcessor" />
     <type name="Magento\Catalog\Model\ResourceModel\Product\CompositeBaseSelectProcessor">
         <arguments>
diff --git a/app/code/Magento/Catalog/view/base/web/js/price-box.js b/app/code/Magento/Catalog/view/base/web/js/price-box.js
index de68d769885fd..783d39cddbc76 100644
--- a/app/code/Magento/Catalog/view/base/web/js/price-box.js
+++ b/app/code/Magento/Catalog/view/base/web/js/price-box.js
@@ -78,11 +78,7 @@ define([
                 pricesCode = [],
                 priceValue, origin, finalPrice;
 
-            if (typeof newPrices !== 'undefined' && newPrices.hasOwnProperty('prices')) {
-                this.cache.additionalPriceObject = {};
-            } else {
-                this.cache.additionalPriceObject = this.cache.additionalPriceObject || {};
-            }
+            this.cache.additionalPriceObject = this.cache.additionalPriceObject || {};
 
             if (newPrices) {
                 $.extend(this.cache.additionalPriceObject, newPrices);
diff --git a/app/code/Magento/CatalogImportExport/Model/Import/Uploader.php b/app/code/Magento/CatalogImportExport/Model/Import/Uploader.php
index 0578cc41d0739..081934dfdfb14 100644
--- a/app/code/Magento/CatalogImportExport/Model/Import/Uploader.php
+++ b/app/code/Magento/CatalogImportExport/Model/Import/Uploader.php
@@ -191,9 +191,9 @@ public function move($fileName, $renameFileOff = false)
             }
 
             $fileName = preg_replace('/[^a-z0-9\._-]+/i', '', $fileName);
-            $filePath = $this->_directory->getRelativePath($filePath . $fileName);
+            $relativePath = $this->_directory->getRelativePath($filePath . $fileName);
             $this->_directory->writeFile(
-                $filePath,
+                $relativePath,
                 $read->readAll()
             );
         }
diff --git a/app/code/Magento/CatalogSearch/Model/Layer/Filter/Attribute.php b/app/code/Magento/CatalogSearch/Model/Layer/Filter/Attribute.php
index 7aac6e98fc044..7b239d84bf962 100644
--- a/app/code/Magento/CatalogSearch/Model/Layer/Filter/Attribute.php
+++ b/app/code/Magento/CatalogSearch/Model/Layer/Filter/Attribute.php
@@ -91,12 +91,10 @@ protected function _getItemsData()
             return $this->itemDataBuilder->build();
         }
 
-        $productSize = $productCollection->getSize();
-
         $options = $attribute->getFrontend()
             ->getSelectOptions();
         foreach ($options as $option) {
-            $this->buildOptionData($option, $isAttributeFilterable, $optionsFacetedData, $productSize);
+            $this->buildOptionData($option, $isAttributeFilterable, $optionsFacetedData);
         }
 
         return $this->itemDataBuilder->build();
@@ -108,17 +106,16 @@ protected function _getItemsData()
      * @param array $option
      * @param boolean $isAttributeFilterable
      * @param array $optionsFacetedData
-     * @param int $productSize
      * @return void
      */
-    private function buildOptionData($option, $isAttributeFilterable, $optionsFacetedData, $productSize)
+    private function buildOptionData($option, $isAttributeFilterable, $optionsFacetedData)
     {
         $value = $this->getOptionValue($option);
         if ($value === false) {
             return;
         }
         $count = $this->getOptionCount($value, $optionsFacetedData);
-        if ($isAttributeFilterable && (!$this->isOptionReducesResults($count, $productSize) || $count === 0)) {
+        if ($isAttributeFilterable && $count === 0) {
             return;
         }
 
diff --git a/app/code/Magento/CatalogSearch/Test/Unit/Model/Layer/Filter/AttributeTest.php b/app/code/Magento/CatalogSearch/Test/Unit/Model/Layer/Filter/AttributeTest.php
index abc0fdd1069fe..69e2c33d02d1a 100644
--- a/app/code/Magento/CatalogSearch/Test/Unit/Model/Layer/Filter/AttributeTest.php
+++ b/app/code/Magento/CatalogSearch/Test/Unit/Model/Layer/Filter/AttributeTest.php
@@ -321,10 +321,6 @@ public function testGetItemsWithoutApply()
             ->method('build')
             ->will($this->returnValue($builtData));
 
-        $this->fulltextCollection->expects($this->once())
-            ->method('getSize')
-            ->will($this->returnValue(50));
-
         $expectedFilterItems = [
             $this->createFilterItem(0, $builtData[0]['label'], $builtData[0]['value'], $builtData[0]['count']),
             $this->createFilterItem(1, $builtData[1]['label'], $builtData[1]['value'], $builtData[1]['count']),
@@ -383,9 +379,6 @@ public function testGetItemsOnlyWithResults()
         $this->fulltextCollection->expects($this->once())
             ->method('getFacetedData')
             ->willReturn($facetedData);
-        $this->fulltextCollection->expects($this->once())
-            ->method('getSize')
-            ->will($this->returnValue(50));
 
         $this->itemDataBuilder->expects($this->once())
             ->method('addItemData')
diff --git a/app/code/Magento/Checkout/Block/Onepage.php b/app/code/Magento/Checkout/Block/Onepage.php
index ca6b045ddbb5d..e01d5835b4cf0 100644
--- a/app/code/Magento/Checkout/Block/Onepage.php
+++ b/app/code/Magento/Checkout/Block/Onepage.php
@@ -38,7 +38,7 @@ class Onepage extends \Magento\Framework\View\Element\Template
     protected $layoutProcessors;
 
     /**
-     * @var \Magento\Framework\Serialize\Serializer\Json
+     * @var \Magento\Framework\Serialize\SerializerInterface
      */
     private $serializer;
 
@@ -48,8 +48,9 @@ class Onepage extends \Magento\Framework\View\Element\Template
      * @param \Magento\Checkout\Model\CompositeConfigProvider $configProvider
      * @param array $layoutProcessors
      * @param array $data
-     * @param \Magento\Framework\Serialize\Serializer\Json|null $serializer
-     * @throws \RuntimeException
+     * @param \Magento\Framework\Serialize\Serializer\Json $serializer
+     * @param \Magento\Framework\Serialize\SerializerInterface $serializerInterface
+     * @SuppressWarnings(PHPMD.UnusedFormalParameter)
      */
     public function __construct(
         \Magento\Framework\View\Element\Template\Context $context,
@@ -57,7 +58,8 @@ public function __construct(
         \Magento\Checkout\Model\CompositeConfigProvider $configProvider,
         array $layoutProcessors = [],
         array $data = [],
-        \Magento\Framework\Serialize\Serializer\Json $serializer = null
+        \Magento\Framework\Serialize\Serializer\Json $serializer = null,
+        \Magento\Framework\Serialize\SerializerInterface $serializerInterface = null
     ) {
         parent::__construct($context, $data);
         $this->formKey = $formKey;
@@ -65,12 +67,12 @@ public function __construct(
         $this->jsLayout = isset($data['jsLayout']) && is_array($data['jsLayout']) ? $data['jsLayout'] : [];
         $this->configProvider = $configProvider;
         $this->layoutProcessors = $layoutProcessors;
-        $this->serializer = $serializer ?: \Magento\Framework\App\ObjectManager::getInstance()
-            ->get(\Magento\Framework\Serialize\Serializer\Json::class);
+        $this->serializer = $serializerInterface ?: \Magento\Framework\App\ObjectManager::getInstance()
+            ->get(\Magento\Framework\Serialize\Serializer\JsonHexTag::class);
     }
 
     /**
-     * @return string
+     * @inheritdoc
      */
     public function getJsLayout()
     {
@@ -78,7 +80,7 @@ public function getJsLayout()
             $this->jsLayout = $processor->process($this->jsLayout);
         }
 
-        return json_encode($this->jsLayout, JSON_HEX_TAG);
+        return $this->serializer->serialize($this->jsLayout);
     }
 
     /**
@@ -115,11 +117,13 @@ public function getBaseUrl()
     }
 
     /**
+     * Retrieve serialized checkout config.
+     *
      * @return bool|string
      * @since 100.2.0
      */
     public function getSerializedCheckoutConfig()
     {
-        return json_encode($this->getCheckoutConfig(), JSON_HEX_TAG);
+        return  $this->serializer->serialize($this->getCheckoutConfig());
     }
 }
diff --git a/app/code/Magento/Checkout/Test/Unit/Block/OnepageTest.php b/app/code/Magento/Checkout/Test/Unit/Block/OnepageTest.php
index 54f77c95148ac..b54339aa2c1d8 100644
--- a/app/code/Magento/Checkout/Test/Unit/Block/OnepageTest.php
+++ b/app/code/Magento/Checkout/Test/Unit/Block/OnepageTest.php
@@ -35,7 +35,7 @@ class OnepageTest extends \PHPUnit\Framework\TestCase
     /**
      * @var \PHPUnit_Framework_MockObject_MockObject
      */
-    private $serializer;
+    private $serializerMock;
 
     protected function setUp()
     {
@@ -49,7 +49,7 @@ protected function setUp()
             \Magento\Checkout\Block\Checkout\LayoutProcessorInterface::class
         );
 
-        $this->serializer = $this->createMock(\Magento\Framework\Serialize\Serializer\Json::class);
+        $this->serializerMock = $this->createMock(\Magento\Framework\Serialize\Serializer\JsonHexTag::class);
 
         $this->model = new \Magento\Checkout\Block\Onepage(
             $contextMock,
@@ -57,7 +57,8 @@ protected function setUp()
             $this->configProviderMock,
             [$this->layoutProcessorMock],
             [],
-            $this->serializer
+            $this->serializerMock,
+            $this->serializerMock
         );
     }
 
@@ -93,6 +94,7 @@ public function testGetJsLayout()
         $processedLayout = ['layout' => ['processed' => true]];
         $jsonLayout = '{"layout":{"processed":true}}';
         $this->layoutProcessorMock->expects($this->once())->method('process')->with([])->willReturn($processedLayout);
+        $this->serializerMock->expects($this->once())->method('serialize')->willReturn($jsonLayout);
 
         $this->assertEquals($jsonLayout, $this->model->getJsLayout());
     }
@@ -101,6 +103,7 @@ public function testGetSerializedCheckoutConfig()
     {
         $checkoutConfig = ['checkout', 'config'];
         $this->configProviderMock->expects($this->once())->method('getConfig')->willReturn($checkoutConfig);
+        $this->serializerMock->expects($this->once())->method('serialize')->willReturn(json_encode($checkoutConfig));
 
         $this->assertEquals(json_encode($checkoutConfig), $this->model->getSerializedCheckoutConfig());
     }
diff --git a/app/code/Magento/Checkout/etc/frontend/di.xml b/app/code/Magento/Checkout/etc/frontend/di.xml
index d80f88786c87b..00bcd2a27005a 100644
--- a/app/code/Magento/Checkout/etc/frontend/di.xml
+++ b/app/code/Magento/Checkout/etc/frontend/di.xml
@@ -59,6 +59,7 @@
                 <item name="totalsSortOrder" xsi:type="object">Magento\Checkout\Block\Checkout\TotalsProcessor</item>
                 <item name="directoryData" xsi:type="object">Magento\Checkout\Block\Checkout\DirectoryDataProcessor</item>
             </argument>
+            <argument name="serializer" xsi:type="object">Magento\Framework\Serialize\Serializer\JsonHexTag</argument>
         </arguments>
     </type>
     <type name="Magento\Checkout\Block\Cart\Totals">
diff --git a/app/code/Magento/Config/Console/Command/ConfigSet/DefaultProcessor.php b/app/code/Magento/Config/Console/Command/ConfigSet/DefaultProcessor.php
index d7d513bfad423..86ae1f96749df 100644
--- a/app/code/Magento/Config/Console/Command/ConfigSet/DefaultProcessor.php
+++ b/app/code/Magento/Config/Console/Command/ConfigSet/DefaultProcessor.php
@@ -7,17 +7,19 @@
 
 use Magento\Config\App\Config\Type\System;
 use Magento\Config\Console\Command\ConfigSetCommand;
+use Magento\Config\Model\Config\Factory as ConfigFactory;
 use Magento\Framework\App\Config\ConfigPathResolver;
 use Magento\Framework\App\DeploymentConfig;
+use Magento\Framework\App\ObjectManager;
 use Magento\Framework\Exception\CouldNotSaveException;
 use Magento\Config\Model\PreparedValueFactory;
-use Magento\Framework\App\Config\Value;
 
 /**
  * Processes default flow of config:set command.
+ *
  * This processor saves the value of configuration into database.
  *
- * {@inheritdoc}
+ * @inheritdoc
  * @api
  * @since 100.2.0
  */
@@ -44,26 +46,36 @@ class DefaultProcessor implements ConfigSetProcessorInterface
      */
     private $preparedValueFactory;
 
+    /**
+     * @var ConfigFactory
+     */
+    private $configFactory;
+
     /**
      * @param PreparedValueFactory $preparedValueFactory The factory for prepared value
      * @param DeploymentConfig $deploymentConfig The deployment configuration reader
      * @param ConfigPathResolver $configPathResolver The resolver for configuration paths according to source type
+     * @param ConfigFactory|null $configFactory
      */
     public function __construct(
         PreparedValueFactory $preparedValueFactory,
         DeploymentConfig $deploymentConfig,
-        ConfigPathResolver $configPathResolver
+        ConfigPathResolver $configPathResolver,
+        ConfigFactory $configFactory = null
     ) {
         $this->preparedValueFactory = $preparedValueFactory;
         $this->deploymentConfig = $deploymentConfig;
         $this->configPathResolver = $configPathResolver;
+
+        $this->configFactory = $configFactory ?? ObjectManager::getInstance()->get(ConfigFactory::class);
     }
 
     /**
      * Processes database flow of config:set command.
+     *
      * Requires installed application.
      *
-     * {@inheritdoc}
+     * @inheritdoc
      * @since 100.2.0
      */
     public function process($path, $value, $scope, $scopeCode)
@@ -78,12 +90,12 @@ public function process($path, $value, $scope, $scopeCode)
         }
 
         try {
-            /** @var Value $backendModel */
-            $backendModel = $this->preparedValueFactory->create($path, $value, $scope, $scopeCode);
-            if ($backendModel instanceof Value) {
-                $resourceModel = $backendModel->getResource();
-                $resourceModel->save($backendModel);
-            }
+            $config = $this->configFactory->create([
+                'scope' => $scope,
+                'scope_code' => $scopeCode,
+            ]);
+            $config->setDataByPath($path, $value);
+            $config->save();
         } catch (\Exception $exception) {
             throw new CouldNotSaveException(__('%1', $exception->getMessage()), $exception);
         }
diff --git a/app/code/Magento/Config/Model/Config.php b/app/code/Magento/Config/Model/Config.php
index 0472c5daa276f..b1074e92cc949 100644
--- a/app/code/Magento/Config/Model/Config.php
+++ b/app/code/Magento/Config/Model/Config.php
@@ -9,15 +9,32 @@
 use Magento\Config\Model\Config\Structure\Element\Group;
 use Magento\Config\Model\Config\Structure\Element\Field;
 use Magento\Framework\App\ObjectManager;
+use Magento\Framework\App\ScopeInterface;
+use Magento\Framework\App\ScopeResolverPool;
+use Magento\Store\Model\ScopeInterface as StoreScopeInterface;
+use Magento\Store\Model\ScopeTypeNormalizer;
 
 /**
  * Backend config model
+ *
  * Used to save configuration
  *
  * @author     Magento Core Team <core@magentocommerce.com>
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
  * @api
  * @since 100.0.2
+ * @method string getSection()
+ * @method void setSection(string $section)
+ * @method string getWebsite()
+ * @method void setWebsite(string $website)
+ * @method string getStore()
+ * @method void setStore(string $store)
+ * @method string getScope()
+ * @method void setScope(string $scope)
+ * @method int getScopeId()
+ * @method void setScopeId(int $scopeId)
+ * @method string getScopeCode()
+ * @method void setScopeCode(string $scopeCode)
  */
 class Config extends \Magento\Framework\DataObject
 {
@@ -87,6 +104,16 @@ class Config extends \Magento\Framework\DataObject
      */
     private $settingChecker;
 
+    /**
+     * @var ScopeResolverPool
+     */
+    private $scopeResolverPool;
+
+    /**
+     * @var ScopeTypeNormalizer
+     */
+    private $scopeTypeNormalizer;
+
     /**
      * @param \Magento\Framework\App\Config\ReinitableConfigInterface $config
      * @param \Magento\Framework\Event\ManagerInterface $eventManager
@@ -97,6 +124,9 @@ class Config extends \Magento\Framework\DataObject
      * @param \Magento\Store\Model\StoreManagerInterface $storeManager
      * @param Config\Reader\Source\Deployed\SettingChecker|null $settingChecker
      * @param array $data
+     * @param ScopeResolverPool|null $scopeResolverPool
+     * @param ScopeTypeNormalizer|null $scopeTypeNormalizer
+     * @SuppressWarnings(PHPMD.ExcessiveParameterList)
      */
     public function __construct(
         \Magento\Framework\App\Config\ReinitableConfigInterface $config,
@@ -107,7 +137,9 @@ public function __construct(
         \Magento\Framework\App\Config\ValueFactory $configValueFactory,
         \Magento\Store\Model\StoreManagerInterface $storeManager,
         SettingChecker $settingChecker = null,
-        array $data = []
+        array $data = [],
+        ScopeResolverPool $scopeResolverPool = null,
+        ScopeTypeNormalizer $scopeTypeNormalizer = null
     ) {
         parent::__construct($data);
         $this->_eventManager = $eventManager;
@@ -117,11 +149,17 @@ public function __construct(
         $this->_configLoader = $configLoader;
         $this->_configValueFactory = $configValueFactory;
         $this->_storeManager = $storeManager;
-        $this->settingChecker = $settingChecker ?: ObjectManager::getInstance()->get(SettingChecker::class);
+        $this->settingChecker = $settingChecker
+            ?? ObjectManager::getInstance()->get(SettingChecker::class);
+        $this->scopeResolverPool = $scopeResolverPool
+            ?? ObjectManager::getInstance()->get(ScopeResolverPool::class);
+        $this->scopeTypeNormalizer = $scopeTypeNormalizer
+            ?? ObjectManager::getInstance()->get(ScopeTypeNormalizer::class);
     }
 
     /**
      * Save config section
+     *
      * Require set: section, website, store and groups
      *
      * @throws \Exception
@@ -504,8 +542,8 @@ public function setDataByPath($path, $value)
     }
 
     /**
-     * Get scope name and scopeId
-     * @todo refactor to scope resolver
+     * Set scope data
+     *
      * @return void
      */
     private function initScope()
@@ -513,31 +551,66 @@ private function initScope()
         if ($this->getSection() === null) {
             $this->setSection('');
         }
+
+        $scope = $this->retrieveScope();
+        $this->setScope($this->scopeTypeNormalizer->normalize($scope->getScopeType()));
+        $this->setScopeCode($scope->getCode());
+        $this->setScopeId($scope->getId());
+
         if ($this->getWebsite() === null) {
-            $this->setWebsite('');
+            $this->setWebsite(StoreScopeInterface::SCOPE_WEBSITES === $this->getScope() ? $scope->getId() : '');
         }
         if ($this->getStore() === null) {
-            $this->setStore('');
+            $this->setStore(StoreScopeInterface::SCOPE_STORES === $this->getScope() ? $scope->getId() : '');
         }
+    }
 
-        if ($this->getStore()) {
-            $scope = 'stores';
-            $store = $this->_storeManager->getStore($this->getStore());
-            $scopeId = (int)$store->getId();
-            $scopeCode = $store->getCode();
-        } elseif ($this->getWebsite()) {
-            $scope = 'websites';
-            $website = $this->_storeManager->getWebsite($this->getWebsite());
-            $scopeId = (int)$website->getId();
-            $scopeCode = $website->getCode();
+    /**
+     * Retrieve scope from initial data
+     *
+     * @return ScopeInterface
+     */
+    private function retrieveScope(): ScopeInterface
+    {
+        $scopeType = $this->getScope();
+        if (!$scopeType) {
+            switch (true) {
+                case $this->getStore():
+                    $scopeType = StoreScopeInterface::SCOPE_STORES;
+                    $scopeIdentifier = $this->getStore();
+                    break;
+                case $this->getWebsite():
+                    $scopeType = StoreScopeInterface::SCOPE_WEBSITES;
+                    $scopeIdentifier = $this->getWebsite();
+                    break;
+                default:
+                    $scopeType = ScopeInterface::SCOPE_DEFAULT;
+                    $scopeIdentifier = null;
+                    break;
+            }
         } else {
-            $scope = 'default';
-            $scopeId = 0;
-            $scopeCode = '';
+            switch (true) {
+                case $this->getScopeId() !== null:
+                    $scopeIdentifier = $this->getScopeId();
+                    break;
+                case $this->getScopeCode() !== null:
+                    $scopeIdentifier = $this->getScopeCode();
+                    break;
+                case $this->getStore() !== null:
+                    $scopeIdentifier = $this->getStore();
+                    break;
+                case $this->getWebsite() !== null:
+                    $scopeIdentifier = $this->getWebsite();
+                    break;
+                default:
+                    $scopeIdentifier = null;
+                    break;
+            }
         }
-        $this->setScope($scope);
-        $this->setScopeId($scopeId);
-        $this->setScopeCode($scopeCode);
+        $scope = $this->scopeResolverPool->get($scopeType)
+            ->getScope($scopeIdentifier);
+
+        return $scope;
     }
 
     /**
diff --git a/app/code/Magento/Config/Model/Config/Backend/Currency/AbstractCurrency.php b/app/code/Magento/Config/Model/Config/Backend/Currency/AbstractCurrency.php
index 4ae66bfd9692b..25303093ace5d 100644
--- a/app/code/Magento/Config/Model/Config/Backend/Currency/AbstractCurrency.php
+++ b/app/code/Magento/Config/Model/Config/Backend/Currency/AbstractCurrency.php
@@ -14,6 +14,8 @@
 namespace Magento\Config\Model\Config\Backend\Currency;
 
 /**
+ * Base currency class
+ *
  * @api
  * @since 100.0.2
  */
@@ -26,18 +28,19 @@ abstract class AbstractCurrency extends \Magento\Framework\App\Config\Value
      */
     protected function _getAllowedCurrencies()
     {
-        if (!$this->isFormData() || $this->getData('groups/options/fields/allow/inherit')) {
-            return explode(
+        $allowValue = $this->getData('groups/options/fields/allow/value');
+        $allowedCurrencies = $allowValue === null || $this->getData('groups/options/fields/allow/inherit')
+            ? explode(
                 ',',
                 (string)$this->_config->getValue(
                     \Magento\Directory\Model\Currency::XML_PATH_CURRENCY_ALLOW,
                     $this->getScope(),
                     $this->getScopeId()
                 )
-            );
-        }
+            )
+            : (array) $allowValue;
 
-        return (array)$this->getData('groups/options/fields/allow/value');
+        return $allowedCurrencies;
     }
 
     /**
diff --git a/app/code/Magento/Config/Test/Unit/Console/Command/ConfigSet/DefaultProcessorTest.php b/app/code/Magento/Config/Test/Unit/Console/Command/ConfigSet/DefaultProcessorTest.php
index 984e0fe842687..3fb7d9ad21cd4 100644
--- a/app/code/Magento/Config/Test/Unit/Console/Command/ConfigSet/DefaultProcessorTest.php
+++ b/app/code/Magento/Config/Test/Unit/Console/Command/ConfigSet/DefaultProcessorTest.php
@@ -7,13 +7,14 @@
 
 use Magento\Config\App\Config\Type\System;
 use Magento\Config\Console\Command\ConfigSet\DefaultProcessor;
+use Magento\Config\Model\Config;
+use Magento\Config\Model\Config\Factory as ConfigFactory;
 use Magento\Framework\App\Config\ConfigPathResolver;
 use Magento\Framework\App\Config\ScopeConfigInterface;
 use Magento\Framework\App\DeploymentConfig;
 use Magento\Store\Model\ScopeInterface;
 use Magento\Config\Model\PreparedValueFactory;
 use Magento\Framework\App\Config\Value;
-use Magento\Framework\App\Config\ValueInterface;
 use Magento\Framework\Model\ResourceModel\Db\AbstractDb;
 use PHPUnit_Framework_MockObject_MockObject as Mock;
 
@@ -55,17 +56,18 @@ class DefaultProcessorTest extends \PHPUnit\Framework\TestCase
      */
     private $resourceModelMock;
 
+    /**
+     * @var ConfigFactory|Mock
+     */
+    private $configFactory;
+
     /**
      * @inheritdoc
      */
     protected function setUp()
     {
-        $this->deploymentConfigMock = $this->getMockBuilder(DeploymentConfig::class)
-            ->disableOriginalConstructor()
-            ->getMock();
-        $this->configPathResolverMock = $this->getMockBuilder(ConfigPathResolver::class)
-            ->disableOriginalConstructor()
-            ->getMock();
+        $this->deploymentConfigMock = $this->createMock(DeploymentConfig::class);
+        $this->configPathResolverMock = $this->createMock(ConfigPathResolver::class);
         $this->resourceModelMock = $this->getMockBuilder(AbstractDb::class)
             ->disableOriginalConstructor()
             ->setMethods(['save'])
@@ -74,14 +76,14 @@ protected function setUp()
             ->disableOriginalConstructor()
             ->setMethods(['getResource'])
             ->getMock();
-        $this->preparedValueFactoryMock = $this->getMockBuilder(PreparedValueFactory::class)
-            ->disableOriginalConstructor()
-            ->getMock();
+        $this->preparedValueFactoryMock = $this->createMock(PreparedValueFactory::class);
+        $this->configFactory = $this->createMock(ConfigFactory::class);
 
         $this->model = new DefaultProcessor(
             $this->preparedValueFactoryMock,
             $this->deploymentConfigMock,
-            $this->configPathResolverMock
+            $this->configPathResolverMock,
+            $this->configFactory
         );
     }
 
@@ -98,15 +100,14 @@ public function testProcess($path, $value, $scope, $scopeCode)
     {
         $this->configMockForProcessTest($path, $scope, $scopeCode);
 
-        $this->preparedValueFactoryMock->expects($this->once())
-            ->method('create')
-            ->willReturn($this->valueMock);
-        $this->valueMock->expects($this->once())
-            ->method('getResource')
-            ->willReturn($this->resourceModelMock);
-        $this->resourceModelMock->expects($this->once())
+        $config = $this->createMock(Config::class);
+        $this->configFactory->method('create')
+            ->with(['scope' => $scope, 'scope_code' => $scopeCode])
+            ->willReturn($config);
+        $config->method('setDataByPath')
+            ->with($path, $value);
+        $config->expects($this->once())
             ->method('save')
-            ->with($this->valueMock)
             ->willReturnSelf();
 
         $this->model->process($path, $value, $scope, $scopeCode);
@@ -124,28 +125,6 @@ public function processDataProvider()
         ];
     }
 
-    public function testProcessWithWrongValueInstance()
-    {
-        $path = 'test/test/test';
-        $scope = ScopeConfigInterface::SCOPE_TYPE_DEFAULT;
-        $scopeCode = null;
-        $value = 'value';
-        $valueInterfaceMock = $this->getMockBuilder(ValueInterface::class)
-            ->getMockForAbstractClass();
-
-        $this->configMockForProcessTest($path, $scope, $scopeCode);
-
-        $this->preparedValueFactoryMock->expects($this->once())
-            ->method('create')
-            ->willReturn($valueInterfaceMock);
-        $this->valueMock->expects($this->never())
-            ->method('getResource');
-        $this->resourceModelMock->expects($this->never())
-            ->method('save');
-
-        $this->model->process($path, $value, $scope, $scopeCode);
-    }
-
     /**
      * @param string $path
      * @param string $scope
@@ -185,6 +164,9 @@ public function testProcessLockedValue()
             ->method('resolve')
             ->willReturn('system/default/test/test/test');
 
+        $this->configFactory->expects($this->never())
+            ->method('create');
+
         $this->model->process($path, $value, ScopeConfigInterface::SCOPE_TYPE_DEFAULT, null);
     }
 }
diff --git a/app/code/Magento/Config/Test/Unit/Model/ConfigTest.php b/app/code/Magento/Config/Test/Unit/Model/ConfigTest.php
index fcc1ff8b9c70c..bb772f51c0dac 100644
--- a/app/code/Magento/Config/Test/Unit/Model/ConfigTest.php
+++ b/app/code/Magento/Config/Test/Unit/Model/ConfigTest.php
@@ -5,138 +5,183 @@
  */
 namespace Magento\Config\Test\Unit\Model;
 
+use PHPUnit_Framework_MockObject_MockObject as MockObject;
+use Magento\Config\Model\Config;
+use Magento\Framework\App\Config\ReinitableConfigInterface;
+use Magento\Framework\Event\ManagerInterface;
+use Magento\Config\Model\Config\Structure\Reader;
+use Magento\Framework\DB\TransactionFactory;
+use Magento\Config\Model\Config\Loader;
+use Magento\Framework\App\Config\ValueFactory;
+use Magento\Store\Model\StoreManagerInterface;
+use Magento\Config\Model\Config\Structure;
+use Magento\Config\Model\Config\Reader\Source\Deployed\SettingChecker;
+use Magento\Framework\App\ScopeResolverPool;
+use Magento\Framework\App\ScopeResolverInterface;
+use Magento\Framework\App\ScopeInterface;
+use Magento\Store\Model\ScopeTypeNormalizer;
+use Magento\Framework\DB\Transaction;
+use Magento\Framework\App\Config\Value;
+use Magento\Store\Model\Website;
+use Magento\Config\Model\Config\Structure\Element\Group;
+use Magento\Config\Model\Config\Structure\Element\Field;
+
 /**
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
  */
 class ConfigTest extends \PHPUnit\Framework\TestCase
 {
     /**
-     * @var \Magento\Config\Model\Config
+     * @var Config
+     */
+    private $model;
+
+    /**
+     * @var ManagerInterface|MockObject
+     */
+    private $eventManagerMock;
+
+    /**
+     * @var Reader|MockObject
+     */
+    private $structureReaderMock;
+
+    /**
+     * @var TransactionFactory|MockObject
      */
-    protected $_model;
+    private $transFactoryMock;
 
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject
+     * @var ReinitableConfigInterface|MockObject
      */
-    protected $_eventManagerMock;
+    private $appConfigMock;
 
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject
+     * @var Loader|MockObject
      */
-    protected $_structureReaderMock;
+    private $configLoaderMock;
 
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject
+     * @var ValueFactory|MockObject
      */
-    protected $_transFactoryMock;
+    private $dataFactoryMock;
 
     /**
-     * @var \Magento\Framework\App\Config\ReinitableConfigInterface|\PHPUnit_Framework_MockObject_MockObject
+     * @var StoreManagerInterface|MockObject
      */
-    protected $_appConfigMock;
+    private $storeManager;
 
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject
+     * @var Structure|MockObject
      */
-    protected $_applicationMock;
+    private $configStructure;
 
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject
+     * @var SettingChecker|MockObject
      */
-    protected $_configLoaderMock;
+    private $settingsChecker;
 
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject
+     * @var ScopeResolverPool|MockObject
      */
-    protected $_dataFactoryMock;
+    private $scopeResolverPool;
 
     /**
-     * @var \Magento\Store\Model\StoreManagerInterface
+     * @var ScopeResolverInterface|MockObject
      */
-    protected $_storeManager;
+    private $scopeResolver;
 
     /**
-     * @var \Magento\Config\Model\Config\Structure
+     * @var ScopeInterface|MockObject
      */
-    protected $_configStructure;
+    private $scope;
 
     /**
-     * @var \PHPUnit_Framework_MockObject_MockObject
+     * @var ScopeTypeNormalizer|MockObject
      */
-    private $_settingsChecker;
+    private $scopeTypeNormalizer;
 
     protected function setUp()
     {
-        $this->_eventManagerMock = $this->createMock(\Magento\Framework\Event\ManagerInterface::class);
-        $this->_structureReaderMock = $this->createPartialMock(
-            \Magento\Config\Model\Config\Structure\Reader::class,
+        $this->eventManagerMock = $this->createMock(ManagerInterface::class);
+        $this->structureReaderMock = $this->createPartialMock(
+            Reader::class,
             ['getConfiguration']
         );
-        $this->_configStructure = $this->createMock(\Magento\Config\Model\Config\Structure::class);
+        $this->configStructure = $this->createMock(Structure::class);
 
-        $this->_structureReaderMock->expects(
-            $this->any()
-        )->method(
-            'getConfiguration'
-        )->will(
-            $this->returnValue($this->_configStructure)
-        );
+        $this->structureReaderMock->method('getConfiguration')
+            ->willReturn($this->configStructure);
 
-        $this->_transFactoryMock = $this->createPartialMock(
-            \Magento\Framework\DB\TransactionFactory::class,
+        $this->transFactoryMock = $this->createPartialMock(
+            TransactionFactory::class,
             ['create', 'addObject']
         );
-        $this->_appConfigMock = $this->createMock(\Magento\Framework\App\Config\ReinitableConfigInterface::class);
-        $this->_configLoaderMock = $this->createPartialMock(
-            \Magento\Config\Model\Config\Loader::class,
+        $this->appConfigMock = $this->createMock(ReinitableConfigInterface::class);
+        $this->configLoaderMock = $this->createPartialMock(
+            Loader::class,
             ['getConfigByPath']
         );
-        $this->_dataFactoryMock = $this->createMock(\Magento\Framework\App\Config\ValueFactory::class);
-
-        $this->_storeManager = $this->getMockForAbstractClass(\Magento\Store\Model\StoreManagerInterface::class);
-
-        $this->_settingsChecker = $this
-            ->createMock(\Magento\Config\Model\Config\Reader\Source\Deployed\SettingChecker::class);
-
-        $this->_model = new \Magento\Config\Model\Config(
-            $this->_appConfigMock,
-            $this->_eventManagerMock,
-            $this->_configStructure,
-            $this->_transFactoryMock,
-            $this->_configLoaderMock,
-            $this->_dataFactoryMock,
-            $this->_storeManager,
-            $this->_settingsChecker
+        $this->dataFactoryMock = $this->createMock(ValueFactory::class);
+
+        $this->storeManager = $this->createMock(StoreManagerInterface::class);
+
+        $this->settingsChecker = $this->createMock(SettingChecker::class);
+
+        $this->scopeResolverPool = $this->createMock(ScopeResolverPool::class);
+        $this->scopeResolver = $this->createMock(ScopeResolverInterface::class);
+        $this->scopeResolverPool->method('get')
+            ->willReturn($this->scopeResolver);
+        $this->scope = $this->createMock(ScopeInterface::class);
+        $this->scopeResolver->method('getScope')
+            ->willReturn($this->scope);
+
+        $this->scopeTypeNormalizer = $this->createMock(ScopeTypeNormalizer::class);
+
+        $this->model = new Config(
+            $this->appConfigMock,
+            $this->eventManagerMock,
+            $this->configStructure,
+            $this->transFactoryMock,
+            $this->configLoaderMock,
+            $this->dataFactoryMock,
+            $this->storeManager,
+            $this->settingsChecker,
+            [],
+            $this->scopeResolverPool,
+            $this->scopeTypeNormalizer
         );
     }
 
     public function testSaveDoesNotDoAnythingIfGroupsAreNotPassed()
     {
-        $this->_configLoaderMock->expects($this->never())->method('getConfigByPath');
-        $this->_model->save();
+        $this->configLoaderMock->expects($this->never())->method('getConfigByPath');
+        $this->model->save();
     }
 
     public function testSaveEmptiesNonSetArguments()
     {
-        $this->_structureReaderMock->expects($this->never())->method('getConfiguration');
-        $this->assertNull($this->_model->getSection());
-        $this->assertNull($this->_model->getWebsite());
-        $this->assertNull($this->_model->getStore());
-        $this->_model->save();
-        $this->assertSame('', $this->_model->getSection());
-        $this->assertSame('', $this->_model->getWebsite());
-        $this->assertSame('', $this->_model->getStore());
+        $this->structureReaderMock->expects($this->never())->method('getConfiguration');
+        $this->assertNull($this->model->getSection());
+        $this->assertNull($this->model->getWebsite());
+        $this->assertNull($this->model->getStore());
+        $this->model->save();
+        $this->assertSame('', $this->model->getSection());
+        $this->assertSame('', $this->model->getWebsite());
+        $this->assertSame('', $this->model->getStore());
     }
 
     public function testSaveToCheckAdminSystemConfigChangedSectionEvent()
     {
-        $transactionMock = $this->createMock(\Magento\Framework\DB\Transaction::class);
+        $transactionMock = $this->createMock(Transaction::class);
 
-        $this->_transFactoryMock->expects($this->any())->method('create')->will($this->returnValue($transactionMock));
+        $this->transFactoryMock->method('create')
+            ->willReturn($transactionMock);
 
-        $this->_configLoaderMock->expects($this->any())->method('getConfigByPath')->will($this->returnValue([]));
+        $this->configLoaderMock->method('getConfigByPath')
+            ->willReturn([]);
 
-        $this->_eventManagerMock->expects(
+        $this->eventManagerMock->expects(
             $this->at(0)
         )->method(
             'dispatch'
@@ -145,7 +190,7 @@ public function testSaveToCheckAdminSystemConfigChangedSectionEvent()
             $this->arrayHasKey('website')
         );
 
-        $this->_eventManagerMock->expects(
+        $this->eventManagerMock->expects(
             $this->at(0)
         )->method(
             'dispatch'
@@ -154,123 +199,147 @@ public function testSaveToCheckAdminSystemConfigChangedSectionEvent()
             $this->arrayHasKey('store')
         );
 
-        $this->_model->setGroups(['1' => ['data']]);
-        $this->_model->save();
+        $this->model->setGroups(['1' => ['data']]);
+        $this->model->save();
     }
 
     public function testDoNotSaveReadOnlyFields()
     {
-        $transactionMock = $this->createMock(\Magento\Framework\DB\Transaction::class);
-        $this->_transFactoryMock->expects($this->any())->method('create')->will($this->returnValue($transactionMock));
+        $transactionMock = $this->createMock(Transaction::class);
+        $this->transFactoryMock->method('create')
+            ->willReturn($transactionMock);
 
-        $this->_settingsChecker->expects($this->any())->method('isReadOnly')->will($this->returnValue(true));
-        $this->_configLoaderMock->expects($this->any())->method('getConfigByPath')->will($this->returnValue([]));
+        $this->settingsChecker->method('isReadOnly')
+            ->willReturn(true);
+        $this->configLoaderMock->method('getConfigByPath')
+            ->willReturn([]);
 
-        $this->_model->setGroups(['1' => ['fields' => ['key' => ['data']]]]);
-        $this->_model->setSection('section');
+        $this->model->setGroups(['1' => ['fields' => ['key' => ['data']]]]);
+        $this->model->setSection('section');
 
-        $group = $this->createMock(\Magento\Config\Model\Config\Structure\Element\Group::class);
-        $group->method('getPath')->willReturn('section/1');
+        $group = $this->createMock(Group::class);
+        $group->method('getPath')
+            ->willReturn('section/1');
 
-        $field = $this->createMock(\Magento\Config\Model\Config\Structure\Element\Field::class);
-        $field->method('getGroupPath')->willReturn('section/1');
-        $field->method('getId')->willReturn('key');
+        $field = $this->createMock(Field::class);
+        $field->method('getGroupPath')
+            ->willReturn('section/1');
+        $field->method('getId')
+            ->willReturn('key');
 
-        $this->_configStructure->expects($this->at(0))
+        $this->configStructure->expects($this->at(0))
             ->method('getElement')
             ->with('section/1')
-            ->will($this->returnValue($group));
-        $this->_configStructure->expects($this->at(1))
+            ->willReturn($group);
+        $this->configStructure->expects($this->at(1))
             ->method('getElement')
             ->with('section/1')
-            ->will($this->returnValue($group));
-        $this->_configStructure->expects($this->at(2))
+            ->willReturn($group);
+        $this->configStructure->expects($this->at(2))
             ->method('getElement')
             ->with('section/1/key')
-            ->will($this->returnValue($field));
+            ->willReturn($field);
 
         $backendModel = $this->createPartialMock(
-            \Magento\Framework\App\Config\Value::class,
+            Value::class,
             ['addData']
         );
-        $this->_dataFactoryMock->expects($this->any())->method('create')->will($this->returnValue($backendModel));
+        $this->dataFactoryMock->method('create')
+            ->willReturn($backendModel);
 
-        $this->_transFactoryMock->expects($this->never())->method('addObject');
-        $backendModel->expects($this->never())->method('addData');
+        $this->transFactoryMock->expects($this->never())
+            ->method('addObject');
+        $backendModel->expects($this->never())
+            ->method('addData');
 
-        $this->_model->save();
+        $this->model->save();
     }
 
     public function testSaveToCheckScopeDataSet()
     {
-        $transactionMock = $this->createMock(\Magento\Framework\DB\Transaction::class);
-        $this->_transFactoryMock->expects($this->any())->method('create')->will($this->returnValue($transactionMock));
+        $transactionMock = $this->createMock(Transaction::class);
+        $this->transFactoryMock->method('create')
+            ->willReturn($transactionMock);
 
-        $this->_configLoaderMock->expects($this->any())->method('getConfigByPath')->will($this->returnValue([]));
+        $this->configLoaderMock->method('getConfigByPath')
+            ->willReturn([]);
 
-        $this->_eventManagerMock->expects($this->at(0))
+        $this->eventManagerMock->expects($this->at(0))
             ->method('dispatch')
             ->with(
                 $this->equalTo('admin_system_config_changed_section_section'),
                 $this->arrayHasKey('website')
             );
-        $this->_eventManagerMock->expects($this->at(0))
+        $this->eventManagerMock->expects($this->at(0))
             ->method('dispatch')
             ->with(
                 $this->equalTo('admin_system_config_changed_section_section'),
                 $this->arrayHasKey('store')
             );
 
-        $group = $this->createMock(\Magento\Config\Model\Config\Structure\Element\Group::class);
+        $group = $this->createMock(Group::class);
         $group->method('getPath')->willReturn('section/1');
 
-        $field = $this->createMock(\Magento\Config\Model\Config\Structure\Element\Field::class);
+        $field = $this->createMock(Field::class);
         $field->method('getGroupPath')->willReturn('section/1');
         $field->method('getId')->willReturn('key');
 
-        $this->_configStructure->expects($this->at(0))
+        $this->configStructure->expects($this->at(0))
             ->method('getElement')
             ->with('section/1')
-            ->will($this->returnValue($group));
-        $this->_configStructure->expects($this->at(1))
+            ->willReturn($group);
+        $this->configStructure->expects($this->at(1))
             ->method('getElement')
             ->with('section/1')
-            ->will($this->returnValue($group));
-        $this->_configStructure->expects($this->at(2))
+            ->willReturn($group);
+        $this->configStructure->expects($this->at(2))
             ->method('getElement')
             ->with('section/1/key')
-            ->will($this->returnValue($field));
-        $this->_configStructure->expects($this->at(3))
+            ->willReturn($field);
+        $this->configStructure->expects($this->at(3))
             ->method('getElement')
             ->with('section/1')
-            ->will($this->returnValue($group));
-        $this->_configStructure->expects($this->at(4))
+            ->willReturn($group);
+        $this->configStructure->expects($this->at(4))
             ->method('getElement')
             ->with('section/1/key')
-            ->will($this->returnValue($field));
-
-        $website = $this->createMock(\Magento\Store\Model\Website::class);
-        $website->expects($this->any())->method('getCode')->will($this->returnValue('website_code'));
-        $this->_storeManager->expects($this->any())->method('getWebsite')->will($this->returnValue($website));
-        $this->_storeManager->expects($this->any())->method('getWebsites')->will($this->returnValue([$website]));
-        $this->_storeManager->expects($this->any())->method('isSingleStoreMode')->will($this->returnValue(true));
-
-        $this->_model->setWebsite('website');
-        $this->_model->setSection('section');
-        $this->_model->setGroups(['1' => ['fields' => ['key' => ['data']]]]);
+            ->willReturn($field);
+
+        $this->scopeResolver->method('getScope')
+            ->with('1')
+            ->willReturn($this->scope);
+        $this->scope->expects($this->atLeastOnce())
+            ->method('getScopeType')
+            ->willReturn('website');
+        $this->scope->expects($this->atLeastOnce())
+            ->method('getId')
+            ->willReturn(1);
+        $this->scope->expects($this->atLeastOnce())
+            ->method('getCode')
+            ->willReturn('website_code');
+        $this->scopeTypeNormalizer->expects($this->atLeastOnce())
+            ->method('normalize')
+            ->with('website')
+            ->willReturn('websites');
+        $website = $this->createMock(Website::class);
+        $this->storeManager->method('getWebsites')->willReturn([$website]);
+        $this->storeManager->method('isSingleStoreMode')->willReturn(true);
+
+        $this->model->setWebsite('1');
+        $this->model->setSection('section');
+        $this->model->setGroups(['1' => ['fields' => ['key' => ['data']]]]);
 
         $backendModel = $this->createPartialMock(
-            \Magento\Framework\App\Config\Value::class,
+            Value::class,
             ['setPath', 'addData', '__sleep', '__wakeup']
         );
-        $backendModel->expects($this->once())
-            ->method('addData')
+        $backendModel->method('addData')
             ->with([
                 'field' => 'key',
                 'groups' => [1 => ['fields' => ['key' => ['data']]]],
                 'group_id' => null,
                 'scope' => 'websites',
-                'scope_id' => 0,
+                'scope_id' => 1,
                 'scope_code' => 'website_code',
                 'field_config' => null,
                 'fieldset_data' => ['key' => null],
@@ -278,18 +347,19 @@ public function testSaveToCheckScopeDataSet()
         $backendModel->expects($this->once())
             ->method('setPath')
             ->with('section/1/key')
-            ->will($this->returnValue($backendModel));
+            ->willReturn($backendModel);
 
-        $this->_dataFactoryMock->expects($this->any())->method('create')->will($this->returnValue($backendModel));
+        $this->dataFactoryMock->method('create')
+            ->willReturn($backendModel);
 
-        $this->_model->save();
+        $this->model->save();
     }
 
     public function testSetDataByPath()
     {
         $value = 'value';
         $path = '<section>/<group>/<field>';
-        $this->_model->setDataByPath($path, $value);
+        $this->model->setDataByPath($path, $value);
         $expected = [
             'section' => '<section>',
             'groups' => [
@@ -300,7 +370,7 @@ public function testSetDataByPath()
                 ],
             ],
         ];
-        $this->assertSame($expected, $this->_model->getData());
+        $this->assertSame($expected, $this->model->getData());
     }
 
     /**
@@ -309,7 +379,7 @@ public function testSetDataByPath()
      */
     public function testSetDataByPathEmpty()
     {
-        $this->_model->setDataByPath('', 'value');
+        $this->model->setDataByPath('', 'value');
     }
 
     /**
@@ -324,7 +394,7 @@ public function testSetDataByPathWrongDepth($path, $expectedException)
         $this->expectException('\UnexpectedValueException');
         $this->expectExceptionMessage($expectedException);
         $value = 'value';
-        $this->_model->setDataByPath($path, $value);
+        $this->model->setDataByPath($path, $value);
     }
 
     /**
diff --git a/app/code/Magento/ConfigurableProduct/view/frontend/web/js/configurable.js b/app/code/Magento/ConfigurableProduct/view/frontend/web/js/configurable.js
index 6357bbd6c7c0c..1df84d27a5c30 100644
--- a/app/code/Magento/ConfigurableProduct/view/frontend/web/js/configurable.js
+++ b/app/code/Magento/ConfigurableProduct/view/frontend/web/js/configurable.js
@@ -376,7 +376,8 @@ define([
                 basePrice = parseFloat(this.options.spConfig.prices.basePrice.amount),
                 optionFinalPrice,
                 optionPriceDiff,
-                optionPrices = this.options.spConfig.optionPrices;
+                optionPrices = this.options.spConfig.optionPrices,
+                allowedProductMinPrice;
 
             this._clearSelect(element);
             element.options[0] = new Option('', '');
@@ -407,8 +408,8 @@ define([
 
                         if (typeof allowedProducts[0] !== 'undefined' &&
                             typeof optionPrices[allowedProducts[0]] !== 'undefined') {
-
-                            optionFinalPrice = parseFloat(optionPrices[allowedProducts[0]].finalPrice.amount);
+                            allowedProductMinPrice = this._getAllowedProductWithMinPrice(allowedProducts);
+                            optionFinalPrice = parseFloat(optionPrices[allowedProductMinPrice].finalPrice.amount);
                             optionPriceDiff = optionFinalPrice - basePrice;
 
                             if (optionPriceDiff !== 0) {
@@ -489,36 +490,27 @@ define([
         _getPrices: function () {
             var prices = {},
                 elements = _.toArray(this.options.settings),
-                hasProductPrice = false,
-                optionPriceDiff = 0,
-                allowedProduct, optionPrices, basePrice, optionFinalPrice;
+                allowedProduct;
 
             _.each(elements, function (element) {
                 var selected = element.options[element.selectedIndex],
                     config = selected && selected.config,
                     priceValue = {};
 
-                if (config && config.allowedProducts.length === 1 && !hasProductPrice) {
-                    prices = {};
+                if (config && config.allowedProducts.length === 1) {
                     priceValue = this._calculatePrice(config);
-                    hasProductPrice = true;
                 } else if (element.value) {
                     allowedProduct = this._getAllowedProductWithMinPrice(config.allowedProducts);
-                    optionPrices = this.options.spConfig.optionPrices;
-                    basePrice = parseFloat(this.options.spConfig.prices.basePrice.amount);
-
-                    if (!_.isEmpty(allowedProduct)) {
-                        optionFinalPrice = parseFloat(optionPrices[allowedProduct].finalPrice.amount);
-                        optionPriceDiff = optionFinalPrice - basePrice;
-                    }
-
-                    if (optionPriceDiff !== 0) {
-                        prices = {};
-                        priceValue = this._calculatePriceDifference(allowedProduct);
-                    }
+                    priceValue = this._calculatePrice({
+                        'allowedProducts': [
+                            allowedProduct
+                        ]
+                    });
                 }
 
-                prices[element.attributeId] = priceValue;
+                if (!_.isEmpty(priceValue)) {
+                    prices.prices = priceValue;
+                }
             }, this);
 
             return prices;
@@ -539,40 +531,15 @@ define([
             _.each(allowedProducts, function (allowedProduct) {
                 optionFinalPrice = parseFloat(optionPrices[allowedProduct].finalPrice.amount);
 
-                if (_.isEmpty(product)) {
+                if (_.isEmpty(product) || optionFinalPrice < optionMinPrice) {
                     optionMinPrice = optionFinalPrice;
                     product = allowedProduct;
                 }
-
-                if (optionFinalPrice < optionMinPrice) {
-                    product = allowedProduct;
-                }
             }, this);
 
             return product;
         },
 
-        /**
-         * Calculate price difference for allowed product
-         *
-         * @param {*} allowedProduct - Product
-         * @returns {*}
-         * @private
-         */
-        _calculatePriceDifference: function (allowedProduct) {
-            var displayPrices = $(this.options.priceHolderSelector).priceBox('option').prices,
-                newPrices = this.options.spConfig.optionPrices[allowedProduct];
-
-            _.each(displayPrices, function (price, code) {
-
-                if (newPrices[code]) {
-                    displayPrices[code].amount = newPrices[code].amount - displayPrices[code].amount;
-                }
-            });
-
-            return displayPrices;
-        },
-
         /**
          * Returns prices for configured products
          *
diff --git a/app/code/Magento/Paypal/Model/Config/Structure/Element/FieldPlugin.php b/app/code/Magento/Paypal/Model/Config/Structure/Element/FieldPlugin.php
index c2056aea08c00..5d5db0128b1eb 100644
--- a/app/code/Magento/Paypal/Model/Config/Structure/Element/FieldPlugin.php
+++ b/app/code/Magento/Paypal/Model/Config/Structure/Element/FieldPlugin.php
@@ -5,7 +5,6 @@
  */
 namespace Magento\Paypal\Model\Config\Structure\Element;
 
-use Magento\Framework\App\RequestInterface;
 use Magento\Config\Model\Config\Structure\Element\Field as FieldConfigStructure;
 use Magento\Paypal\Model\Config\StructurePlugin as ConfigStructurePlugin;
 
@@ -14,19 +13,6 @@
  */
 class FieldPlugin
 {
-    /**
-     * @var RequestInterface
-     */
-    private $request;
-
-    /**
-     * @param RequestInterface $request
-     */
-    public function __construct(RequestInterface $request)
-    {
-        $this->request = $request;
-    }
-
     /**
      * Get original configPath (not changed by PayPal configuration inheritance)
      *
@@ -36,7 +22,7 @@ public function __construct(RequestInterface $request)
      */
     public function afterGetConfigPath(FieldConfigStructure $subject, $result)
     {
-        if (!$result && $this->request->getParam('section') == 'payment') {
+        if (!$result && strpos($subject->getPath(), 'payment_') === 0) {
             $result = preg_replace(
                 '@^(' . implode('|', ConfigStructurePlugin::getPaypalConfigCountries(true)) . ')/@',
                 'payment/',
diff --git a/app/code/Magento/Paypal/Test/Unit/Model/Config/Structure/Element/FieldPluginTest.php b/app/code/Magento/Paypal/Test/Unit/Model/Config/Structure/Element/FieldPluginTest.php
index 8615b91383aaa..72c13c80b31e4 100644
--- a/app/code/Magento/Paypal/Test/Unit/Model/Config/Structure/Element/FieldPluginTest.php
+++ b/app/code/Magento/Paypal/Test/Unit/Model/Config/Structure/Element/FieldPluginTest.php
@@ -7,7 +7,6 @@
 
 use Magento\Paypal\Model\Config\Structure\Element\FieldPlugin as FieldConfigStructurePlugin;
 use Magento\Framework\TestFramework\Unit\Helper\ObjectManager as ObjectManagerHelper;
-use Magento\Framework\App\RequestInterface;
 use Magento\Config\Model\Config\Structure\Element\Field as FieldConfigStructureMock;
 
 class FieldPluginTest extends \PHPUnit\Framework\TestCase
@@ -22,11 +21,6 @@ class FieldPluginTest extends \PHPUnit\Framework\TestCase
      */
     private $objectManagerHelper;
 
-    /**
-     * @var RequestInterface|\PHPUnit_Framework_MockObject_MockObject
-     */
-    private $requestMock;
-
     /**
      * @var FieldConfigStructureMock|\PHPUnit_Framework_MockObject_MockObject
      */
@@ -34,16 +28,13 @@ class FieldPluginTest extends \PHPUnit\Framework\TestCase
 
     protected function setUp()
     {
-        $this->requestMock = $this->getMockBuilder(RequestInterface::class)
-            ->getMockForAbstractClass();
         $this->subjectMock = $this->getMockBuilder(FieldConfigStructureMock::class)
             ->disableOriginalConstructor()
             ->getMock();
 
         $this->objectManagerHelper = new ObjectManagerHelper($this);
         $this->plugin = $this->objectManagerHelper->getObject(
-            FieldConfigStructurePlugin::class,
-            ['request' => $this->requestMock]
+            FieldConfigStructurePlugin::class
         );
     }
 
@@ -56,10 +47,8 @@ public function testAroundGetConfigPathHasResult()
 
     public function testAroundGetConfigPathNonPaymentSection()
     {
-        $this->requestMock->expects(static::once())
-            ->method('getParam')
-            ->with('section')
-            ->willReturn('non-payment');
+        $this->subjectMock->method('getPath')
+            ->willReturn('non-payment/group/field');
 
         $this->assertNull($this->plugin->afterGetConfigPath($this->subjectMock, null));
     }
@@ -72,12 +61,7 @@ public function testAroundGetConfigPathNonPaymentSection()
      */
     public function testAroundGetConfigPath($subjectPath, $expectedConfigPath)
     {
-        $this->requestMock->expects(static::once())
-            ->method('getParam')
-            ->with('section')
-            ->willReturn('payment');
-        $this->subjectMock->expects(static::once())
-            ->method('getPath')
+        $this->subjectMock->method('getPath')
             ->willReturn($subjectPath);
 
         $this->assertEquals($expectedConfigPath, $this->plugin->afterGetConfigPath($this->subjectMock, null));
diff --git a/app/code/Magento/Review/Model/ResourceModel/Rating.php b/app/code/Magento/Review/Model/ResourceModel/Rating.php
index 3f54c17f6ff7c..9cd9b0650a278 100644
--- a/app/code/Magento/Review/Model/ResourceModel/Rating.php
+++ b/app/code/Magento/Review/Model/ResourceModel/Rating.php
@@ -425,9 +425,11 @@ public function getReviewSummary($object, $onlyForCurrentStore = true)
 
         $data = $connection->fetchAll($select, [':review_id' => $object->getReviewId()]);
 
+        $currentStore = $this->_storeManager->isSingleStoreMode() ? $this->_storeManager->getStore()->getId() : null;
+
         if ($onlyForCurrentStore) {
             foreach ($data as $row) {
-                if ($row['store_id'] == $this->_storeManager->getStore()->getId()) {
+                if ($row['store_id'] !== $currentStore) {
                     $object->addData($row);
                 }
             }
diff --git a/app/code/Magento/Sales/Block/Adminhtml/Order/Create/Form/Account.php b/app/code/Magento/Sales/Block/Adminhtml/Order/Create/Form/Account.php
index 0f92fa2320e89..b61a5cf83734b 100644
--- a/app/code/Magento/Sales/Block/Adminhtml/Order/Create/Form/Account.php
+++ b/app/code/Magento/Sales/Block/Adminhtml/Order/Create/Form/Account.php
@@ -11,6 +11,7 @@
 use Magento\Framework\Api\ExtensibleDataObjectConverter;
 use Magento\Framework\Data\Form\Element\AbstractElement;
 use Magento\Framework\Pricing\PriceCurrencyInterface;
+use Magento\Store\Model\ScopeInterface;
 
 /**
  * Create order account form
@@ -134,15 +135,8 @@ protected function _prepareForm()
         $this->_addAttributesToForm($attributes, $fieldset);
 
         $this->_form->addFieldNameSuffix('order[account]');
-
-        $formValues = $this->getFormValues();
-        foreach ($attributes as $code => $attribute) {
-            $defaultValue = $attribute->getDefaultValue();
-            if (isset($defaultValue) && !isset($formValues[$code])) {
-                $formValues[$code] = $defaultValue;
-            }
-        }
-        $this->_form->setValues($formValues);
+        $storeId = (int)$this->_sessionQuote->getStoreId();
+        $this->_form->setValues($this->extractValuesFromAttributes($attributes, $storeId));
 
         return $this;
     }
@@ -189,4 +183,42 @@ public function getFormValues()
 
         return $data;
     }
+
+    /**
+     * Extract the form values from attributes.
+     *
+     * @param array $attributes
+     * @param int $storeId
+     * @return array
+     */
+    private function extractValuesFromAttributes(array $attributes, int $storeId): array
+    {
+        $formValues = $this->getFormValues();
+        foreach ($attributes as $code => $attribute) {
+            $defaultValue = $attribute->getDefaultValue();
+            if (isset($defaultValue) && !isset($formValues[$code])) {
+                $formValues[$code] = $defaultValue;
+            }
+            if ($code === 'group_id' && empty($defaultValue)) {
+                $formValues[$code] = $this->getDefaultCustomerGroup($storeId);
+            }
+        }
+
+        return $formValues;
+    }
+
+    /**
+     * Gets default customer group.
+     *
+     * @param int $storeId
+     * @return string|null
+     */
+    private function getDefaultCustomerGroup(int $storeId)
+    {
+        return $this->_scopeConfig->getValue(
+            'customer/create_account/default_group',
+            ScopeInterface::SCOPE_STORE,
+            $storeId
+        );
+    }
 }
diff --git a/app/code/Magento/Sales/Block/Adminhtml/Order/Create/Sidebar/Cart.php b/app/code/Magento/Sales/Block/Adminhtml/Order/Create/Sidebar/Cart.php
index 34d7a3f8ee25e..8179c0e8d282a 100644
--- a/app/code/Magento/Sales/Block/Adminhtml/Order/Create/Sidebar/Cart.php
+++ b/app/code/Magento/Sales/Block/Adminhtml/Order/Create/Sidebar/Cart.php
@@ -3,8 +3,13 @@
  * Copyright © Magento, Inc. All rights reserved.
  * See COPYING.txt for license details.
  */
+declare(strict_types=1);
+
 namespace Magento\Sales\Block\Adminhtml\Order\Create\Sidebar;
 
+use Magento\Catalog\Model\Product;
+use Magento\Catalog\Pricing\Price\FinalPrice;
+
 /**
  * Adminhtml sales order create sidebar cart block
  *
@@ -58,6 +63,17 @@ public function getItemCollection()
         return $collection;
     }
 
+    /**
+     * @inheritdoc
+     */
+    public function getItemPrice(Product $product)
+    {
+        $customPrice = $this->getCartItemCustomPrice($product);
+        $price = $customPrice ?? $product->getPriceInfo()->getPrice(FinalPrice::PRICE_CODE)->getValue();
+
+        return $this->convertPrice($price);
+    }
+
     /**
      * Retrieve display item qty availability
      *
@@ -111,4 +127,23 @@ protected function _prepareLayout()
 
         return parent::_prepareLayout();
     }
+
+    /**
+     * Returns cart item custom price.
+     *
+     * @param Product $product
+     * @return float|null
+     */
+    private function getCartItemCustomPrice(Product $product)
+    {
+        $items = $this->getItemCollection();
+        foreach ($items as $item) {
+            $productItemId = $this->getProduct($item)->getId();
+            if ($productItemId === $product->getId() && $item->getCustomPrice()) {
+                return (float)$item->getCustomPrice();
+            }
+        }
+
+        return null;
+    }
 }
diff --git a/app/code/Magento/Sales/view/adminhtml/layout/sales_order_create_customer_block.xml b/app/code/Magento/Sales/view/adminhtml/layout/sales_order_create_customer_block.xml
index c321bee460e46..0f5a3559f3008 100644
--- a/app/code/Magento/Sales/view/adminhtml/layout/sales_order_create_customer_block.xml
+++ b/app/code/Magento/Sales/view/adminhtml/layout/sales_order_create_customer_block.xml
@@ -80,13 +80,13 @@
                             <argument name="align" xsi:type="string">center</argument>
                         </arguments>
                     </block>
-                </block>
-                <block class="Magento\Backend\Block\Widget\Grid\Column" name="adminhtml.customer.grid.columnSet.website_name" as="website_name">
-                    <arguments>
-                        <argument name="header" xsi:type="string" translate="true">Website</argument>
-                        <argument name="index" xsi:type="string">website_name</argument>
-                        <argument name="align" xsi:type="string">center</argument>
-                    </arguments>
+                    <block class="Magento\Backend\Block\Widget\Grid\Column" name="adminhtml.customer.grid.columnSet.website_name" as="website_name">
+                        <arguments>
+                            <argument name="header" xsi:type="string" translate="true">Website</argument>
+                            <argument name="index" xsi:type="string">website_name</argument>
+                            <argument name="align" xsi:type="string">center</argument>
+                        </arguments>
+                    </block>
                 </block>
             </block>
         </referenceBlock>
diff --git a/app/code/Magento/Sales/view/adminhtml/templates/items/column/name.phtml b/app/code/Magento/Sales/view/adminhtml/templates/items/column/name.phtml
index ebdf79fe7f008..98cc0d1d0ad07 100644
--- a/app/code/Magento/Sales/view/adminhtml/templates/items/column/name.phtml
+++ b/app/code/Magento/Sales/view/adminhtml/templates/items/column/name.phtml
@@ -28,7 +28,7 @@
                 <dt><?= $block->escapeHtml($_option['label']) ?>:</dt>
                 <dd>
                     <?php if (isset($_option['custom_view']) && $_option['custom_view']): ?>
-                        <?= $block->escapeHtml($block->getCustomizedOptionValue($_option)) ?>
+                    <?= /* @escapeNotVerified */ $block->getCustomizedOptionValue($_option) ?>
                     <?php else: ?>
                         <?php $_option = $block->getFormattedOption($_option['value']); ?>
                         <?= $block->escapeHtml($_option['value']) ?>
diff --git a/app/code/Magento/Store/etc/di.xml b/app/code/Magento/Store/etc/di.xml
index 3d740bfee2093..83f891d06647d 100644
--- a/app/code/Magento/Store/etc/di.xml
+++ b/app/code/Magento/Store/etc/di.xml
@@ -232,6 +232,7 @@
     <type name="Magento\Framework\App\ScopeResolverPool">
         <arguments>
             <argument name="scopeResolvers" xsi:type="array">
+                <item name="default" xsi:type="object">Magento\Framework\App\ScopeResolver</item>
                 <item name="store" xsi:type="object">Magento\Store\Model\Resolver\Store</item>
                 <item name="stores" xsi:type="object">Magento\Store\Model\Resolver\Store</item>
                 <item name="group" xsi:type="object">Magento\Store\Model\Resolver\Group</item>
diff --git a/app/code/Magento/Swatches/view/frontend/web/js/swatch-renderer.js b/app/code/Magento/Swatches/view/frontend/web/js/swatch-renderer.js
index 4b8a96f57e53e..1145d3acc11ed 100644
--- a/app/code/Magento/Swatches/view/frontend/web/js/swatch-renderer.js
+++ b/app/code/Magento/Swatches/view/frontend/web/js/swatch-renderer.js
@@ -1030,14 +1030,10 @@ define([
             _.each(allowedProducts, function (allowedProduct) {
                 optionFinalPrice = parseFloat(optionPrices[allowedProduct].finalPrice.amount);
 
-                if (_.isEmpty(product)) {
+                if (_.isEmpty(product) || optionFinalPrice < optionMinPrice) {
                     optionMinPrice = optionFinalPrice;
                     product = allowedProduct;
                 }
-
-                if (optionFinalPrice < optionMinPrice) {
-                    product = allowedProduct;
-                }
             }, this);
 
             return product;
diff --git a/app/code/Magento/Ui/TemplateEngine/Xhtml/Result.php b/app/code/Magento/Ui/TemplateEngine/Xhtml/Result.php
index 066b4494e51d0..14283a8899e50 100644
--- a/app/code/Magento/Ui/TemplateEngine/Xhtml/Result.php
+++ b/app/code/Magento/Ui/TemplateEngine/Xhtml/Result.php
@@ -5,6 +5,8 @@
  */
 namespace Magento\Ui\TemplateEngine\Xhtml;
 
+use Magento\Framework\App\ObjectManager;
+use Magento\Framework\Serialize\Serializer\JsonHexTag;
 use Magento\Framework\View\Layout\Generator\Structure;
 use Magento\Framework\View\Element\UiComponentInterface;
 use Magento\Framework\View\TemplateEngine\Xhtml\Template;
@@ -42,25 +44,33 @@ class Result implements ResultInterface
      */
     protected $logger;
 
+    /**
+     * @var JsonHexTag
+     */
+    private $jsonSerializer;
+
     /**
      * @param Template $template
      * @param CompilerInterface $compiler
      * @param UiComponentInterface $component
      * @param Structure $structure
      * @param LoggerInterface $logger
+     * @param JsonHexTag $jsonSerializer
      */
     public function __construct(
         Template $template,
         CompilerInterface $compiler,
         UiComponentInterface $component,
         Structure $structure,
-        LoggerInterface $logger
+        LoggerInterface $logger,
+        JsonHexTag $jsonSerializer = null
     ) {
         $this->template = $template;
         $this->compiler = $compiler;
         $this->component = $component;
         $this->structure = $structure;
         $this->logger = $logger;
+        $this->jsonSerializer = $jsonSerializer ?? ObjectManager::getInstance()->get(JsonHexTag::class);
     }
 
     /**
@@ -81,7 +91,7 @@ public function getDocumentElement()
     public function appendLayoutConfiguration()
     {
         $layoutConfiguration = $this->wrapContent(
-            json_encode($this->structure->generate($this->component), JSON_HEX_TAG)
+            $this->jsonSerializer->serialize($this->structure->generate($this->component))
         );
         $this->template->append($layoutConfiguration);
     }
diff --git a/app/code/Magento/Ui/Test/Unit/TemplateEngine/Xhtml/ResultTest.php b/app/code/Magento/Ui/Test/Unit/TemplateEngine/Xhtml/ResultTest.php
index 30a8e8005bbe8..9babfefd87f76 100644
--- a/app/code/Magento/Ui/Test/Unit/TemplateEngine/Xhtml/ResultTest.php
+++ b/app/code/Magento/Ui/Test/Unit/TemplateEngine/Xhtml/ResultTest.php
@@ -6,6 +6,7 @@
 
 namespace Magento\Ui\Test\Unit\TemplateEngine\Xhtml;
 
+use Magento\Framework\Serialize\Serializer\JsonHexTag;
 use Magento\Framework\TestFramework\Unit\Helper\ObjectManager;
 use Magento\Framework\View\Layout\Generator\Structure;
 use Magento\Framework\View\Element\UiComponentInterface;
@@ -58,6 +59,11 @@ class ResultTest extends \PHPUnit\Framework\TestCase
      */
     private $objectManager;
 
+    /**
+     * @var JsonHexTag|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $serializer;
+
     protected function setUp()
     {
         $this->template = $this->createPartialMock(Template::class, ['append']);
@@ -65,6 +71,9 @@ protected function setUp()
         $this->component = $this->createMock(UiComponentInterface::class);
         $this->structure = $this->createPartialMock(Structure::class, ['generate']);
         $this->logger = $this->createMock(LoggerInterface::class);
+        $this->serializer = $this->getMockBuilder(JsonHexTag::class)
+            ->disableOriginalConstructor()
+            ->getMock();
 
         $this->objectManager = new ObjectManager($this);
         $this->testModel = $this->objectManager->getObject(Result::class, [
@@ -73,6 +82,7 @@ protected function setUp()
             'component' => $this->component,
             'structure' => $this->structure,
             'logger' => $this->logger,
+            'jsonSerializer' => $this->serializer
         ]);
     }
 
@@ -82,6 +92,10 @@ protected function setUp()
     public function testAppendLayoutConfiguration()
     {
         $configWithCdata = 'text before <![CDATA[cdata text]]>';
+        $this->serializer->expects($this->once())
+            ->method('serialize')
+            ->with([$configWithCdata])
+            ->willReturn('["text before \u003C![CDATA[cdata text]]\u003E"]');
         $this->structure->expects($this->once())
             ->method('generate')
             ->with($this->component)
diff --git a/app/code/Magento/Ui/view/base/web/templates/grid/filters/elements/ui-select.html b/app/code/Magento/Ui/view/base/web/templates/grid/filters/elements/ui-select.html
index 4038f65738041..a96a4163caf7e 100644
--- a/app/code/Magento/Ui/view/base/web/templates/grid/filters/elements/ui-select.html
+++ b/app/code/Magento/Ui/view/base/web/templates/grid/filters/elements/ui-select.html
@@ -36,7 +36,7 @@
             class="action-select admin__action-multiselect"
             data-role="advanced-select"
             data-bind="
-            css: {_active: multiselectFocus},
+            css: {_active: listVisible},
             click: function(data, event) {
                 toggleListVisible(data, event)
             }
@@ -52,7 +52,7 @@
             class="action-select admin__action-multiselect"
             data-role="advanced-select"
             data-bind="
-            css: {_active: multiselectFocus},
+            css: {_active: listVisible},
             click: function(data, event) {
                 toggleListVisible(data, event)
             }
diff --git a/app/design/adminhtml/Magento/backend/web/css/source/forms/_controls.less b/app/design/adminhtml/Magento/backend/web/css/source/forms/_controls.less
index 5f1cee13b5b88..44a086ac61392 100644
--- a/app/design/adminhtml/Magento/backend/web/css/source/forms/_controls.less
+++ b/app/design/adminhtml/Magento/backend/web/css/source/forms/_controls.less
@@ -85,7 +85,7 @@
         cursor: pointer;
     }
 
-    &:focus {
+    &:active {
         background-image+: url('../images/arrows-bg.svg');
         background-position+: ~'calc(100% - 12px)' 13px;
 
diff --git a/app/design/frontend/Magento/luma/Magento_Theme/web/css/source/_module.less b/app/design/frontend/Magento/luma/Magento_Theme/web/css/source/_module.less
index 0ba135f69a315..f3e0f810481ed 100644
--- a/app/design/frontend/Magento/luma/Magento_Theme/web/css/source/_module.less
+++ b/app/design/frontend/Magento/luma/Magento_Theme/web/css/source/_module.less
@@ -325,6 +325,23 @@
             }
         }
     }
+    .page-header {
+        .switcher {
+            .options {
+                ul.dropdown {
+                    right: 0;
+                    &:before {
+                        left: auto;
+                        right: 10px;
+                    }
+                    &:after {
+                        left: auto;
+                        right: 9px;
+                    }
+                }
+            }
+        }
+    }
 
     //
     //  Widgets
diff --git a/app/etc/di.xml b/app/etc/di.xml
index ad77ae3adc566..05fd34a178ded 100755
--- a/app/etc/di.xml
+++ b/app/etc/di.xml
@@ -1356,4 +1356,11 @@
             <argument name="scopeType" xsi:type="const">Magento\Framework\App\Config\ScopeConfigInterface::SCOPE_TYPE_DEFAULT</argument>
         </arguments>
     </type>
+    <type name="Magento\Framework\App\ScopeResolverPool">
+        <arguments>
+            <argument name="scopeResolvers" xsi:type="array">
+                <item name="default" xsi:type="object">Magento\Framework\App\ScopeResolver</item>
+            </argument>
+        </arguments>
+    </type>
 </config>
diff --git a/dev/tests/integration/testsuite/Magento/Catalog/Model/ProductExternalTest.php b/dev/tests/integration/testsuite/Magento/Catalog/Model/ProductExternalTest.php
index 8370e514dc2f2..a1923e63972ee 100644
--- a/dev/tests/integration/testsuite/Magento/Catalog/Model/ProductExternalTest.php
+++ b/dev/tests/integration/testsuite/Magento/Catalog/Model/ProductExternalTest.php
@@ -69,7 +69,7 @@ public function testGetCategoryId()
     {
         $this->assertFalse($this->_model->getCategoryId());
         $category = new \Magento\Framework\DataObject(['id' => 5]);
-
+        $this->_model->setCategoryIds([5]);
         $this->objectManager->get(\Magento\Framework\Registry::class)->register('current_category', $category);
         try {
             $this->assertEquals(5, $this->_model->getCategoryId());
@@ -83,6 +83,7 @@ public function testGetCategoryId()
     public function testGetCategory()
     {
         $this->assertEmpty($this->_model->getCategory());
+        $this->_model->setCategoryIds([3]);
 
         $this->objectManager->get(\Magento\Framework\Registry::class)
             ->register('current_category', new \Magento\Framework\DataObject(['id' => 3]));
diff --git a/dev/tests/integration/testsuite/Magento/Catalog/Model/RemoveRedundantImageTest.php b/dev/tests/integration/testsuite/Magento/Catalog/Model/RemoveRedundantImageTest.php
new file mode 100644
index 0000000000000..1bc545a25ac32
--- /dev/null
+++ b/dev/tests/integration/testsuite/Magento/Catalog/Model/RemoveRedundantImageTest.php
@@ -0,0 +1,82 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\Catalog\Model;
+
+use Magento\Framework\App\Filesystem\DirectoryList;
+use Magento\Framework\Filesystem;
+use Magento\Framework\Filesystem\Directory\WriteInterface;
+use Magento\Framework\ObjectManagerInterface;
+
+/**
+ * Test removing old Category Image file from pub/media/catalog/category directory if such Image is not used anymore.
+ */
+class RemoveRedundantImageTest extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * @var ObjectManagerInterface
+     */
+    private $objectManager;
+
+    /**
+     * @var Filesystem
+     */
+    private $filesystem;
+
+    /**
+     * @var WriteInterface
+     */
+    private $mediaDirectory;
+
+    /**
+     * @var CategoryRepository
+     */
+    private $categoryRepository;
+
+    protected function setUp()
+    {
+        $this->objectManager = \Magento\TestFramework\Helper\Bootstrap::getObjectManager();
+        /** @var Filesystem $filesystem */
+        $this->filesystem = $this->objectManager->get(Filesystem::class);
+        $this->mediaDirectory = $this->filesystem->getDirectoryWrite(DirectoryList::MEDIA);
+        $this->categoryRepository = $this->objectManager->get(CategoryRepository::class);
+    }
+
+    /**
+     * Tests removing Image file if it is not used anymore.
+     *
+     * @magentoDataFixture Magento/Catalog/_files/categories_with_image.php
+     *
+     * @magentoAppIsolation enabled
+     * @magentoDbIsolation enabled
+     */
+    public function testRemoveRedundantImage()
+    {
+        $imagesPath = 'catalog' . DIRECTORY_SEPARATOR . 'category';
+        $absoluteImagesPath = $this->mediaDirectory->getAbsolutePath($imagesPath);
+        $filePath1 = $absoluteImagesPath . DIRECTORY_SEPARATOR . 'test_image_1.jpg';
+        $filePath2 = $absoluteImagesPath . DIRECTORY_SEPARATOR . 'test_image_2.jpg';
+        $this->mediaDirectory->create($absoluteImagesPath);
+        $this->mediaDirectory->touch($filePath1);
+        $this->mediaDirectory->touch($filePath2);
+
+        $category1 = $this->categoryRepository->get(3);
+        $category1->setImage('test_image_3.jpg');
+        $this->categoryRepository->save($category1);
+        $category2 = $this->categoryRepository->get(5);
+        $category2->setImage('test_image_3.jpg');
+        $this->categoryRepository->save($category2);
+
+        $this->assertTrue($this->mediaDirectory->isExist($filePath1));
+        $this->assertFalse($this->mediaDirectory->isExist($filePath2));
+    }
+
+    protected function tearDown()
+    {
+        $this->mediaDirectory->delete();
+    }
+}
diff --git a/dev/tests/integration/testsuite/Magento/Catalog/_files/categories_with_image.php b/dev/tests/integration/testsuite/Magento/Catalog/_files/categories_with_image.php
new file mode 100644
index 0000000000000..6fc0f4e8b6efa
--- /dev/null
+++ b/dev/tests/integration/testsuite/Magento/Catalog/_files/categories_with_image.php
@@ -0,0 +1,53 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+$objectManager = \Magento\TestFramework\Helper\Bootstrap::getObjectManager();
+
+/**
+ * After installation system has two categories: root one with ID:1 and Default category with ID:2
+ */
+/** @var $category \Magento\Catalog\Model\Category */
+$category = $objectManager->create(\Magento\Catalog\Model\Category::class);
+$category->isObjectNew(true);
+$category->setId(3)
+    ->setName('Category 1')
+    ->setParentId(2)
+    ->setPath('1/2/3')
+    ->setLevel(2)
+    ->setAvailableSortBy('name')
+    ->setDefaultSortBy('name')
+    ->setIsActive(true)
+    ->setPosition(1)
+    ->setImage('test_image_1.jpg')
+    ->save();
+
+$category = $objectManager->create(\Magento\Catalog\Model\Category::class);
+$category->isObjectNew(true);
+$category->setId(4)
+    ->setName('Category 1.1')
+    ->setParentId(3)
+    ->setPath('1/2/3/4')
+    ->setLevel(3)
+    ->setAvailableSortBy('name')
+    ->setDefaultSortBy('name')
+    ->setIsActive(true)
+    ->setIsAnchor(true)
+    ->setPosition(1)
+    ->setImage('test_image_1.jpg')
+    ->save();
+
+$category = $objectManager->create(\Magento\Catalog\Model\Category::class);
+$category->isObjectNew(true);
+$category->setId(5)
+    ->setName('Category 2')
+    ->setParentId(2)
+    ->setPath('1/2/5')
+    ->setLevel(2)
+    ->setAvailableSortBy('name')
+    ->setDefaultSortBy('name')
+    ->setIsActive(true)
+    ->setPosition(2)
+    ->setImage('test_image_2.jpg')
+    ->save();
diff --git a/dev/tests/integration/testsuite/Magento/Catalog/_files/categories_with_image_rollback.php b/dev/tests/integration/testsuite/Magento/Catalog/_files/categories_with_image_rollback.php
new file mode 100644
index 0000000000000..d290a164f639e
--- /dev/null
+++ b/dev/tests/integration/testsuite/Magento/Catalog/_files/categories_with_image_rollback.php
@@ -0,0 +1,23 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+$objectManager = \Magento\TestFramework\Helper\Bootstrap::getObjectManager();
+/** @var \Magento\Framework\Registry $registry */
+$registry = $objectManager->get(\Magento\Framework\Registry::class);
+
+$registry->unregister('isSecureArea');
+$registry->register('isSecureArea', true);
+
+//Remove categories
+/** @var Magento\Catalog\Model\ResourceModel\Category\Collection $collection */
+$collection = $objectManager->create(\Magento\Catalog\Model\ResourceModel\Category\Collection::class);
+$collection
+    ->addAttributeToFilter('level', 2)
+    ->load()
+    ->delete();
+
+$registry->unregister('isSecureArea');
+$registry->register('isSecureArea', false);
diff --git a/dev/tests/integration/testsuite/Magento/CatalogImportExport/Model/Import/ProductTest.php b/dev/tests/integration/testsuite/Magento/CatalogImportExport/Model/Import/ProductTest.php
index 2e1e6b6be970e..139d1d97525bc 100644
--- a/dev/tests/integration/testsuite/Magento/CatalogImportExport/Model/Import/ProductTest.php
+++ b/dev/tests/integration/testsuite/Magento/CatalogImportExport/Model/Import/ProductTest.php
@@ -741,7 +741,6 @@ protected function getOptionValues(\Magento\Catalog\Model\Product\Option $option
     /**
      * Test that product import with images works properly
      *
-     * @magentoDataIsolation enabled
      * @magentoDataFixture mediaImportImageFixture
      * @magentoAppIsolation enabled
      * @SuppressWarnings(PHPMD.ExcessiveMethodLength)
@@ -792,7 +791,6 @@ public function testSaveMediaImage()
     /**
      * Test that errors occurred during importing images are logged.
      *
-     * @magentoDataIsolation enabled
      * @magentoAppIsolation enabled
      * @magentoDataFixture mediaImportImageFixture
      * @magentoDataFixture mediaImportImageFixtureError
@@ -2190,7 +2188,6 @@ public function testImportWithDifferentSkuCase()
     /**
      * Test that product import with images for non-default store works properly.
      *
-     * @magentoDataIsolation enabled
      * @magentoDataFixture mediaImportImageFixture
      * @magentoAppIsolation enabled
      */
@@ -2237,7 +2234,6 @@ public function testProductsWithMultipleStoresWhenMediaIsDisabled()
     /**
      * Test that imported product stock status with backorders functionality enabled can be set to 'out of stock'.
      *
-     * @magentoDataIsolation enabled
      * @magentoAppIsolation enabled
      */
     public function testImportWithBackordersEnabled()
@@ -2364,7 +2360,6 @@ public function testImportProductWithUpdateUrlKey()
     /**
      * Test that product import with non existing images does not broke roles on existing images.
      *
-     * @magentoDataIsolation enabled
      * @magentoDataFixture mediaImportImageFixture
      * @magentoAppIsolation enabled
      * @return void
diff --git a/dev/tests/integration/testsuite/Magento/Config/Console/Command/ConfigSetCommandTest.php b/dev/tests/integration/testsuite/Magento/Config/Console/Command/ConfigSetCommandTest.php
index 3f333a36c9c93..a1998c6c89536 100644
--- a/dev/tests/integration/testsuite/Magento/Config/Console/Command/ConfigSetCommandTest.php
+++ b/dev/tests/integration/testsuite/Magento/Config/Console/Command/ConfigSetCommandTest.php
@@ -27,7 +27,7 @@
 /**
  * Tests the different flows of config:set command.
  *
- * {@inheritdoc}
+ * @inheritdoc
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
  * @magentoDbIsolation enabled
  */
@@ -291,8 +291,7 @@ public function runExtendedDataProvider()
      * @param string $scope
      * @param $scopeCode string|null
      * @dataProvider configSetValidationErrorDataProvider
-     *
-     * @magentoDbIsolation enabled
+     * @magentoDbIsolation disabled
      */
     public function testConfigSetValidationError(
         $path,
@@ -306,6 +305,7 @@ public function testConfigSetValidationError(
 
     /**
      * Data provider for testConfigSetValidationError
+     *
      * @return array
      */
     public function configSetValidationErrorDataProvider()
@@ -398,7 +398,6 @@ public function testConfigSetCurrency()
      * Saving values with successful validation
      *
      * @dataProvider configSetValidDataProvider
-     *
      * @magentoDbIsolation enabled
      */
     public function testConfigSetValid()
diff --git a/dev/tests/integration/testsuite/Magento/Sales/Block/Adminhtml/Order/Create/Form/AccountTest.php b/dev/tests/integration/testsuite/Magento/Sales/Block/Adminhtml/Order/Create/Form/AccountTest.php
index 999522a49e006..ce3f3a3e1fc8e 100644
--- a/dev/tests/integration/testsuite/Magento/Sales/Block/Adminhtml/Order/Create/Form/AccountTest.php
+++ b/dev/tests/integration/testsuite/Magento/Sales/Block/Adminhtml/Order/Create/Form/AccountTest.php
@@ -11,26 +11,37 @@
 namespace Magento\Sales\Block\Adminhtml\Order\Create\Form;
 
 use Magento\Backend\Model\Session\Quote as SessionQuote;
+use Magento\Customer\Api\Data\AttributeMetadataInterface;
 use Magento\Customer\Api\Data\AttributeMetadataInterfaceFactory;
+use Magento\Customer\Model\Data\Option;
 use Magento\Customer\Model\Metadata\Form;
 use Magento\Customer\Model\Metadata\FormFactory;
 use Magento\Framework\View\LayoutInterface;
 use Magento\Quote\Model\Quote;
 use Magento\TestFramework\Helper\Bootstrap;
+use Magento\TestFramework\ObjectManager;
+use PHPUnit\Framework\MockObject\MockObject;
 
 /**
  * @magentoAppArea adminhtml
  */
 class AccountTest extends \PHPUnit\Framework\TestCase
 {
-    /** @var Account */
+    /**
+     * @var Account
+     */
     private $accountBlock;
 
     /**
-     * @var Bootstrap
+     * @var ObjectManager
      */
     private $objectManager;
 
+    /**
+     * @var SessionQuote|MockObject
+     */
+    private $session;
+
     /**
      * @magentoDataFixture Magento/Sales/_files/quote.php
      */
@@ -38,19 +49,23 @@ protected function setUp()
     {
         $this->objectManager = Bootstrap::getObjectManager();
         $quote = $this->objectManager->create(Quote::class)->load(1);
-        $sessionQuoteMock = $this->getMockBuilder(
-            SessionQuote::class
-        )->disableOriginalConstructor()->setMethods(
-            ['getCustomerId', 'getStore', 'getStoreId', 'getQuote']
-        )->getMock();
-        $sessionQuoteMock->expects($this->any())->method('getCustomerId')->will($this->returnValue(1));
-        $sessionQuoteMock->expects($this->any())->method('getQuote')->will($this->returnValue($quote));
+
+        $this->session = $this->getMockBuilder(SessionQuote::class)
+            ->disableOriginalConstructor()
+            ->setMethods(['getCustomerId', 'getStore', 'getStoreId', 'getQuote', 'getQuoteId'])
+            ->getMock();
+        $this->session->method('getCustomerId')
+            ->willReturn(1);
+        $this->session->method('getQuote')
+            ->willReturn($quote);
+        $this->session->method('getQuoteId')
+            ->willReturn($quote->getId());
         /** @var LayoutInterface $layout */
         $layout = $this->objectManager->get(LayoutInterface::class);
         $this->accountBlock = $layout->createBlock(
             Account::class,
             'address_block' . rand(),
-            ['sessionQuote' => $sessionQuoteMock]
+            ['sessionQuote' => $this->session]
         );
         parent::setUp();
     }
@@ -62,13 +77,13 @@ public function testGetForm()
     {
         $expectedFields = ['group_id', 'email'];
         $form = $this->accountBlock->getForm();
-        $this->assertEquals(1, $form->getElements()->count(), "Form has invalid number of fieldsets");
+        self::assertEquals(1, $form->getElements()->count(), "Form has invalid number of fieldsets");
         $fieldset = $form->getElements()[0];
 
-        $this->assertEquals(count($expectedFields), $fieldset->getElements()->count());
+        self::assertEquals(count($expectedFields), $fieldset->getElements()->count());
 
         foreach ($fieldset->getElements() as $element) {
-            $this->assertTrue(
+            self::assertTrue(
                 in_array($element->getId(), $expectedFields),
                 sprintf('Unexpected field "%s" in form.', $element->getId())
             );
@@ -79,6 +94,7 @@ public function testGetForm()
      * Tests a case when user defined custom attribute has default value.
      *
      * @magentoDataFixture Magento/Customer/_files/customer.php
+     * @magentoConfigFixture current_store customer/create_account/default_group 3
      */
     public function testGetFormWithUserDefinedAttribute()
     {
@@ -91,18 +107,27 @@ public function testGetFormWithUserDefinedAttribute()
 
         $form = $accountBlock->getForm();
         $form->setUseContainer(true);
+        $content = $form->toHtml();
 
-        $this->assertContains(
+        self::assertContains(
             '<option value="1" selected="selected">Yes</option>',
-            $form->toHtml(),
-            'Default value for user defined custom attribute should be selected'
+            $content,
+            'Default value for user defined custom attribute should be selected.'
+        );
+
+        self::assertContains(
+            '<option value="3" selected="selected">Customer Group 1</option>',
+            $content,
+            'The Customer Group specified for the chosen store should be selected.'
         );
     }
 
     /**
-     * @return \PHPUnit_Framework_MockObject_MockObject
+     * Creates a mock for Form object.
+     *
+     * @return MockObject
      */
-    private function getFormFactoryMock(): \PHPUnit_Framework_MockObject_MockObject
+    private function getFormFactoryMock()
     {
         /** @var AttributeMetadataInterfaceFactory $attributeMetadataFactory */
         $attributeMetadataFactory = $this->objectManager->create(AttributeMetadataInterfaceFactory::class);
@@ -113,11 +138,12 @@ private function getFormFactoryMock(): \PHPUnit_Framework_MockObject_MockObject
             ->setDefaultValue('1')
             ->setFrontendLabel('Yes/No');
 
+        /** @var Form|MockObject $form */
         $form = $this->getMockBuilder(Form::class)
             ->disableOriginalConstructor()
             ->getMock();
         $form->method('getUserAttributes')->willReturn([$booleanAttribute]);
-        $form->method('getSystemAttributes')->willReturn([]);
+        $form->method('getSystemAttributes')->willReturn([$this->createCustomerGroupAttribute()]);
 
         $formFactory = $this->getMockBuilder(FormFactory::class)
             ->disableOriginalConstructor()
@@ -126,4 +152,33 @@ private function getFormFactoryMock(): \PHPUnit_Framework_MockObject_MockObject
 
         return $formFactory;
     }
+
+    /**
+     * Creates a customer group attribute object.
+     *
+     * @return AttributeMetadataInterface
+     */
+    private function createCustomerGroupAttribute(): AttributeMetadataInterface
+    {
+        /** @var Option $option1 */
+        $option1 = $this->objectManager->create(Option::class);
+        $option1->setValue(3);
+        $option1->setLabel('Customer Group 1');
+
+        /** @var Option $option2 */
+        $option2 = $this->objectManager->create(Option::class);
+        $option2->setValue(4);
+        $option2->setLabel('Customer Group 2');
+
+        /** @var AttributeMetadataInterfaceFactory $attributeMetadataFactory */
+        $attributeMetadataFactory = $this->objectManager->create(AttributeMetadataInterfaceFactory::class);
+        $attribute = $attributeMetadataFactory->create()
+            ->setAttributeCode('group_id')
+            ->setBackendType('static')
+            ->setFrontendInput('select')
+            ->setOptions([$option1, $option2])
+            ->setIsRequired(true);
+
+        return $attribute;
+    }
 }
diff --git a/lib/internal/Magento/Framework/App/ScopeDefault.php b/lib/internal/Magento/Framework/App/ScopeDefault.php
index 2ea62387145bf..e62d19f9ffbb4 100644
--- a/lib/internal/Magento/Framework/App/ScopeDefault.php
+++ b/lib/internal/Magento/Framework/App/ScopeDefault.php
@@ -17,7 +17,7 @@ class ScopeDefault implements ScopeInterface
      */
     public function getCode()
     {
-        return 'default';
+        return '';
     }
 
     /**
@@ -27,7 +27,7 @@ public function getCode()
      */
     public function getId()
     {
-        return 1;
+        return 0;
     }
 
     /**
diff --git a/lib/internal/Magento/Framework/Serialize/README.md b/lib/internal/Magento/Framework/Serialize/README.md
index 5af8fb7f71b6b..d900f89208a54 100644
--- a/lib/internal/Magento/Framework/Serialize/README.md
+++ b/lib/internal/Magento/Framework/Serialize/README.md
@@ -3,6 +3,7 @@
 **Serialize** library provides interface *SerializerInterface* and multiple implementations:
 
  * *Json* - default implementation. Uses PHP native json_encode/json_decode functions;
+ * *JsonHexTag* - default implementation. Uses PHP native json_encode/json_decode functions with `JSON_HEX_TAG` option enabled;
  * *Serialize* - less secure than *Json*, but gives higher performance on big arrays. Uses PHP native serialize/unserialize functions, does not unserialize objects on PHP 7.
  
 Using *Serialize* implementation directly is discouraged, always use *SerializerInterface*, using *Serialize* implementation may lead to security vulnerabilities.
\ No newline at end of file
diff --git a/lib/internal/Magento/Framework/Serialize/Serializer/JsonHexTag.php b/lib/internal/Magento/Framework/Serialize/Serializer/JsonHexTag.php
new file mode 100644
index 0000000000000..4a5406ff3fd99
--- /dev/null
+++ b/lib/internal/Magento/Framework/Serialize/Serializer/JsonHexTag.php
@@ -0,0 +1,35 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+declare(strict_types=1);
+
+namespace Magento\Framework\Serialize\Serializer;
+
+use Magento\Framework\Serialize\SerializerInterface;
+
+/**
+ * Serialize data to JSON with the JSON_HEX_TAG option enabled
+ * (All < and > are converted to \u003C and \u003E),
+ * unserialize JSON encoded data
+ *
+ * @api
+ * @since 100.2.0
+ */
+class JsonHexTag extends Json implements SerializerInterface
+{
+    /**
+     * @inheritDoc
+     * @since 100.2.0
+     */
+    public function serialize($data): string
+    {
+        $result = json_encode($data, JSON_HEX_TAG);
+        if (false === $result) {
+            throw new \InvalidArgumentException('Unable to serialize value.');
+        }
+        return $result;
+    }
+}
diff --git a/lib/internal/Magento/Framework/Serialize/Test/Unit/Serializer/JsonHexTagTest.php b/lib/internal/Magento/Framework/Serialize/Test/Unit/Serializer/JsonHexTagTest.php
new file mode 100644
index 0000000000000..c867dced0fc6e
--- /dev/null
+++ b/lib/internal/Magento/Framework/Serialize/Test/Unit/Serializer/JsonHexTagTest.php
@@ -0,0 +1,118 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+declare(strict_types=1);
+
+namespace Magento\Framework\Serialize\Test\Unit\Serializer;
+
+use Magento\Framework\DataObject;
+use Magento\Framework\Serialize\Serializer\JsonHexTag;
+
+class JsonHexTagTest extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * @var \Magento\Framework\Serialize\Serializer\Json
+     */
+    private $json;
+    
+    protected function setUp()
+    {
+        $objectManager = new \Magento\Framework\TestFramework\Unit\Helper\ObjectManager($this);
+        $this->json = $objectManager->getObject(JsonHexTag::class);
+    }
+
+    /**
+     * @param string|int|float|bool|array|null $value
+     * @param string $expected
+     * @dataProvider serializeDataProvider
+     */
+    public function testSerialize($value, $expected)
+    {
+        $this->assertEquals(
+            $expected,
+            $this->json->serialize($value)
+        );
+    }
+
+    public function serializeDataProvider()
+    {
+        $dataObject = new DataObject(['something']);
+        return [
+            ['', '""'],
+            ['string', '"string"'],
+            [null, 'null'],
+            [false, 'false'],
+            [['a' => 'b', 'd' => 123], '{"a":"b","d":123}'],
+            [123, '123'],
+            [10.56, '10.56'],
+            [$dataObject, '{}'],
+            ['< >', '"\u003C \u003E"'],
+        ];
+    }
+
+    /**
+     * @param string $value
+     * @param string|int|float|bool|array|null $expected
+     * @dataProvider unserializeDataProvider
+     */
+    public function testUnserialize($value, $expected)
+    {
+        $this->assertEquals(
+            $expected,
+            $this->json->unserialize($value)
+        );
+    }
+
+    /**
+     * @return array
+     */
+    public function unserializeDataProvider(): array
+    {
+        return [
+            ['""', ''],
+            ['"string"', 'string'],
+            ['null', null],
+            ['false', false],
+            ['{"a":"b","d":123}', ['a' => 'b', 'd' => 123]],
+            ['123', 123],
+            ['10.56', 10.56],
+            ['{}', []],
+            ['"\u003C \u003E"', '< >'],
+        ];
+    }
+
+    /**
+     * @expectedException \InvalidArgumentException
+     * @expectedExceptionMessage Unable to serialize value.
+     */
+    public function testSerializeException()
+    {
+        $this->json->serialize(STDOUT);
+    }
+
+    /**
+     * @expectedException \InvalidArgumentException
+     * @expectedExceptionMessage Unable to unserialize value.
+     * @dataProvider unserializeExceptionDataProvider
+     */
+    public function testUnserializeException($value)
+    {
+        $this->json->unserialize($value);
+    }
+
+    /**
+     * @return array
+     */
+    public function unserializeExceptionDataProvider(): array
+    {
+        return [
+            [''],
+            [false],
+            [null],
+            ['{']
+        ];
+    }
+}