diff --git a/Classes/Event/Listener/RenderTranslatedFlagInFrontendPreviewMode.php b/Classes/Event/Listener/RenderTranslatedFlagInFrontendPreviewMode.php
index eaffb0b0..d91f48c5 100644
--- a/Classes/Event/Listener/RenderTranslatedFlagInFrontendPreviewMode.php
+++ b/Classes/Event/Listener/RenderTranslatedFlagInFrontendPreviewMode.php
@@ -7,13 +7,11 @@
 use TYPO3\CMS\Core\Context\Context;
 use TYPO3\CMS\Frontend\Controller\TypoScriptFrontendController;
 use TYPO3\CMS\Frontend\Event\AfterCacheableContentIsGeneratedEvent;
-use WebVision\Deepltranslate\Core\Hooks\DeeplPreviewFlagGeneratePageHook;
 
 /**
  * Event listener to render the frontend preview flag information.
  *
- * TYPO3 v12+ only and this is the counter-part of the {@see DeeplPreviewFlagGeneratePageHook} for older TYPO3 versions.
- * https://docs.typo3.org/c/typo3/cms-core/main/en-us/Changelog/12.0/Breaking-97862-HooksRelatedToGeneratingPageContentRemoved.html
+ * @internal for `deepltranslate-core` internal usage and not part of public API.
  */
 final class RenderTranslatedFlagInFrontendPreviewMode
 {
diff --git a/Classes/Hooks/DeeplPreviewFlagGeneratePageHook.php b/Classes/Hooks/DeeplPreviewFlagGeneratePageHook.php
deleted file mode 100644
index 90b73233..00000000
--- a/Classes/Hooks/DeeplPreviewFlagGeneratePageHook.php
+++ /dev/null
@@ -1,59 +0,0 @@
-<?php
-
-declare(strict_types=1);
-
-namespace WebVision\Deepltranslate\Core\Hooks;
-
-use TYPO3\CMS\Core\Context\Exception\AspectNotFoundException;
-use TYPO3\CMS\Frontend\Controller\TypoScriptFrontendController;
-
-class DeeplPreviewFlagGeneratePageHook
-{
-    /**
-     * @param array{pObj: TypoScriptFrontendController} $params
-     * @throws AspectNotFoundException
-     */
-    public function renderDeeplPreviewFlag(array $params): void
-    {
-        $controller = $params['pObj'];
-
-        $isInPreviewMode = $controller->getContext()->hasAspect('frontend.preview')
-            && $controller->getContext()->getPropertyFromAspect('frontend.preview', 'isPreview');
-        if (
-            !$isInPreviewMode
-            || $controller->getContext()->getPropertyFromAspect('workspace', 'isOffline', false)
-            || ($controller->config['config']['disablePreviewNotification'] ?? false)
-            || (
-                isset($controller->page['tx_wvdeepltranslate_translated_time'])
-                && $controller->page['tx_wvdeepltranslate_translated_time'] === 0
-            )
-        ) {
-            return;
-        }
-
-        $messagePreviewLabel = $controller->config['config']['deepl_message_preview'] ?? '';
-        if ($messagePreviewLabel === '') {
-            $messagePreviewLabel = 'Translated with DeepL';
-        }
-
-        $styles = [];
-        $styles[] = 'position: fixed';
-        $styles[] = 'top: 65px';
-        $styles[] = 'right: 15px';
-        $styles[] = 'padding: 8px 18px';
-        $styles[] = 'background: #006494';
-        $styles[] = 'border: 1px solid #006494';
-        $styles[] = 'font-family: sans-serif';
-        $styles[] = 'font-size: 14px';
-        $styles[] = 'font-weight: bold';
-        $styles[] = 'color: #fff';
-        $styles[] = 'z-index: 20000';
-        $styles[] = 'user-select: none';
-        $styles[] = 'pointer-events: none';
-        $styles[] = 'text-align: center';
-        $styles[] = 'border-radius: 2px';
-        $message = '<div id="deepl-preview-info" style="' . implode(';', $styles) . '">' . htmlspecialchars($messagePreviewLabel) . '</div>';
-
-        $controller->content = str_ireplace('</body>', $message . '</body>', $controller->content);
-    }
-}
diff --git a/Configuration/Services.php b/Configuration/Services.php
index d122d354..1ce04c01 100644
--- a/Configuration/Services.php
+++ b/Configuration/Services.php
@@ -9,7 +9,6 @@
 use TYPO3\CMS\Core\Cache\CacheManager;
 use TYPO3\CMS\Core\Cache\Frontend\FrontendInterface;
 use TYPO3\CMS\Core\DependencyInjection\SingletonPass;
-use TYPO3\CMS\Core\Information\Typo3Version;
 use TYPO3\CMS\Dashboard\WidgetRegistry;
 use WebVision\Deepltranslate\Core\Client;
 use WebVision\Deepltranslate\Core\ClientInterface;
@@ -35,8 +34,6 @@
 use WebVision\Deepltranslate\Core\Widgets\UsageWidget;
 
 return function (ContainerConfigurator $containerConfigurator, ContainerBuilder $containerBuilder) {
-    $typo3version = new Typo3Version();
-
     $services = $containerConfigurator
         ->services();
     $services->defaults()
@@ -162,17 +159,14 @@
             ]
         );
 
-    if ((new Typo3Version())->getMajorVersion() >= 12) {
-        // @todo Unnest this in next major when TYPO3 v11 support has been removed.
-        $services
-            ->set(RenderTranslatedFlagInFrontendPreviewMode::class)
-            ->tag(
-                'event.listener',
-                [
-                    'identifier' => 'deepltranslate-core/render-translated-flag-in-frontend-preview-mode',
-                ]
-            );
-    }
+    $services
+        ->set(RenderTranslatedFlagInFrontendPreviewMode::class)
+        ->tag(
+            'event.listener',
+            [
+                'identifier' => 'deepltranslate-core/render-translated-flag-in-frontend-preview-mode',
+            ]
+        );
 
     /**
      * Check if WidgetRegistry is defined, which means that EXT:dashboard is available.
diff --git a/ext_localconf.php b/ext_localconf.php
index 76dff73f..5ca4866d 100644
--- a/ext_localconf.php
+++ b/ext_localconf.php
@@ -26,12 +26,6 @@
     $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['t3lib/class.t3lib_tcemain.php']['checkModifyAccessList']['deepl']
         = \WebVision\Deepltranslate\Core\Hooks\TCEmainHook::class;
 
-    if ($typo3version->getMajorVersion() < 12) {
-        // @todo Remove when TYPO3 v11 support is removed.
-        $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['tslib/class.tslib_fe.php']['contentPostProc-all']['deepl-1675946132'] =
-            \WebVision\WvDeepltranslate\Hooks\DeeplPreviewFlagGeneratePageHook::class . '->renderDeeplPreviewFlag';
-    }
-
     //xclass localizationcontroller for localizeRecords() and process() action
     $GLOBALS['TYPO3_CONF_VARS']['SYS']['Objects'][\TYPO3\CMS\Backend\Controller\Page\LocalizationController::class] = [
         'className' => \WebVision\Deepltranslate\Core\Override\LocalizationController::class,