diff --git a/core/Migrations/Version31000Date20240814184402.php b/core/Migrations/Version31000Date20240814184402.php
new file mode 100644
index 0000000000000..482c548a074ff
--- /dev/null
+++ b/core/Migrations/Version31000Date20240814184402.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OC\Core\Migrations;
+
+use Closure;
+use OCP\DB\ISchemaWrapper;
+use OCP\DB\Types;
+use OCP\Migration\Attributes\AddColumn;
+use OCP\Migration\Attributes\AddIndex;
+use OCP\Migration\Attributes\ColumnType;
+use OCP\Migration\Attributes\IndexType;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+/**
+ * Create new column and index for lazy loading in preferences for the new IUserPreferences API.
+ */
+#[AddColumn(table: 'preferences', name: 'lazy', type: ColumnType::SMALLINT, description: 'lazy loading to user preferences')]
+#[AddColumn(table: 'preferences', name: 'type', type: ColumnType::SMALLINT, description: 'typed values to user preferences')]
+#[AddIndex(table: 'preferences', type: IndexType::INDEX, description: 'new index including lazy flag')]
+class Version31000Date20240814184402 extends SimpleMigrationStep {
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		$table = $schema->getTable('preferences');
+		$table->addColumn('lazy', Types::SMALLINT, ['notnull' => true, 'default' => 0, 'length' => 1, 'unsigned' => true]);
+		$table->addColumn('type', Types::INTEGER, ['notnull' => true, 'default' => 2, 'unsigned' => true]);
+		$table->addIndex(['userid', 'lazy'], 'up_uid_lazy_i');
+
+		return $schema;
+	}
+}
diff --git a/lib/composer/composer/autoload_classmap.php b/lib/composer/composer/autoload_classmap.php
index b8d0dd35f123d..bbd04b64902fb 100644
--- a/lib/composer/composer/autoload_classmap.php
+++ b/lib/composer/composer/autoload_classmap.php
@@ -832,6 +832,13 @@
     'OCP\\UserMigration\\ISizeEstimationMigrator' => $baseDir . '/lib/public/UserMigration/ISizeEstimationMigrator.php',
     'OCP\\UserMigration\\TMigratorBasicVersionHandling' => $baseDir . '/lib/public/UserMigration/TMigratorBasicVersionHandling.php',
     'OCP\\UserMigration\\UserMigrationException' => $baseDir . '/lib/public/UserMigration/UserMigrationException.php',
+    'OCP\\UserPreferences\\Exceptions\\IncorrectTypeException' => $baseDir . '/lib/public/UserPreferences/Exceptions/IncorrectTypeException.php',
+    'OCP\\UserPreferences\\Exceptions\\TypeConflictException' => $baseDir . '/lib/public/UserPreferences/Exceptions/TypeConflictException.php',
+    'OCP\\UserPreferences\\Exceptions\\UnknownKeyException' => $baseDir . '/lib/public/UserPreferences/Exceptions/UnknownKeyException.php',
+    'OCP\\UserPreferences\\Exceptions\\UserPreferencesException' => $baseDir . '/lib/public/UserPreferences/Exceptions/UserPreferencesException.php',
+    'OCP\\UserPreferences\\IUserPreferences' => $baseDir . '/lib/public/UserPreferences/IUserPreferences.php',
+    'OCP\\UserPreferences\\ValueType' => $baseDir . '/lib/public/UserPreferences/ValueType.php',
+    'OCP\\UserPreferences\\ValueTypeDefinition' => $baseDir . '/lib/public/UserPreferences/ValueTypeDefinition.php',
     'OCP\\UserStatus\\IManager' => $baseDir . '/lib/public/UserStatus/IManager.php',
     'OCP\\UserStatus\\IProvider' => $baseDir . '/lib/public/UserStatus/IProvider.php',
     'OCP\\UserStatus\\IUserStatus' => $baseDir . '/lib/public/UserStatus/IUserStatus.php',
@@ -1374,6 +1381,7 @@
     'OC\\Core\\Migrations\\Version30000Date20240717111406' => $baseDir . '/core/Migrations/Version30000Date20240717111406.php',
     'OC\\Core\\Migrations\\Version30000Date20240814180800' => $baseDir . '/core/Migrations/Version30000Date20240814180800.php',
     'OC\\Core\\Migrations\\Version30000Date20240815080800' => $baseDir . '/core/Migrations/Version30000Date20240815080800.php',
+    'OC\\Core\\Migrations\\Version31000Date20240814184402' => $baseDir . '/core/Migrations/Version31000Date20240814184402.php',
     'OC\\Core\\Notification\\CoreNotifier' => $baseDir . '/core/Notification/CoreNotifier.php',
     'OC\\Core\\ResponseDefinitions' => $baseDir . '/core/ResponseDefinitions.php',
     'OC\\Core\\Service\\LoginFlowV2Service' => $baseDir . '/core/Service/LoginFlowV2Service.php',
@@ -1983,6 +1991,7 @@
     'OC\\Updater\\Exceptions\\ReleaseMetadataException' => $baseDir . '/lib/private/Updater/Exceptions/ReleaseMetadataException.php',
     'OC\\Updater\\ReleaseMetadata' => $baseDir . '/lib/private/Updater/ReleaseMetadata.php',
     'OC\\Updater\\VersionCheck' => $baseDir . '/lib/private/Updater/VersionCheck.php',
+    'OC\\UserPreferences' => $baseDir . '/lib/private/UserPreferences.php',
     'OC\\UserStatus\\ISettableProvider' => $baseDir . '/lib/private/UserStatus/ISettableProvider.php',
     'OC\\UserStatus\\Manager' => $baseDir . '/lib/private/UserStatus/Manager.php',
     'OC\\User\\AvailabilityCoordinator' => $baseDir . '/lib/private/User/AvailabilityCoordinator.php',
diff --git a/lib/composer/composer/autoload_static.php b/lib/composer/composer/autoload_static.php
index 646a41626b7b6..19c9018db05a0 100644
--- a/lib/composer/composer/autoload_static.php
+++ b/lib/composer/composer/autoload_static.php
@@ -865,6 +865,13 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OCP\\UserMigration\\ISizeEstimationMigrator' => __DIR__ . '/../../..' . '/lib/public/UserMigration/ISizeEstimationMigrator.php',
         'OCP\\UserMigration\\TMigratorBasicVersionHandling' => __DIR__ . '/../../..' . '/lib/public/UserMigration/TMigratorBasicVersionHandling.php',
         'OCP\\UserMigration\\UserMigrationException' => __DIR__ . '/../../..' . '/lib/public/UserMigration/UserMigrationException.php',
+        'OCP\\UserPreferences\\Exceptions\\IncorrectTypeException' => __DIR__ . '/../../..' . '/lib/public/UserPreferences/Exceptions/IncorrectTypeException.php',
+        'OCP\\UserPreferences\\Exceptions\\TypeConflictException' => __DIR__ . '/../../..' . '/lib/public/UserPreferences/Exceptions/TypeConflictException.php',
+        'OCP\\UserPreferences\\Exceptions\\UnknownKeyException' => __DIR__ . '/../../..' . '/lib/public/UserPreferences/Exceptions/UnknownKeyException.php',
+        'OCP\\UserPreferences\\Exceptions\\UserPreferencesException' => __DIR__ . '/../../..' . '/lib/public/UserPreferences/Exceptions/UserPreferencesException.php',
+        'OCP\\UserPreferences\\IUserPreferences' => __DIR__ . '/../../..' . '/lib/public/UserPreferences/IUserPreferences.php',
+        'OCP\\UserPreferences\\ValueType' => __DIR__ . '/../../..' . '/lib/public/UserPreferences/ValueType.php',
+        'OCP\\UserPreferences\\ValueTypeDefinition' => __DIR__ . '/../../..' . '/lib/public/UserPreferences/ValueTypeDefinition.php',
         'OCP\\UserStatus\\IManager' => __DIR__ . '/../../..' . '/lib/public/UserStatus/IManager.php',
         'OCP\\UserStatus\\IProvider' => __DIR__ . '/../../..' . '/lib/public/UserStatus/IProvider.php',
         'OCP\\UserStatus\\IUserStatus' => __DIR__ . '/../../..' . '/lib/public/UserStatus/IUserStatus.php',
@@ -1407,6 +1414,7 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OC\\Core\\Migrations\\Version30000Date20240717111406' => __DIR__ . '/../../..' . '/core/Migrations/Version30000Date20240717111406.php',
         'OC\\Core\\Migrations\\Version30000Date20240814180800' => __DIR__ . '/../../..' . '/core/Migrations/Version30000Date20240814180800.php',
         'OC\\Core\\Migrations\\Version30000Date20240815080800' => __DIR__ . '/../../..' . '/core/Migrations/Version30000Date20240815080800.php',
+        'OC\\Core\\Migrations\\Version31000Date20240814184402' => __DIR__ . '/../../..' . '/core/Migrations/Version31000Date20240814184402.php',
         'OC\\Core\\Notification\\CoreNotifier' => __DIR__ . '/../../..' . '/core/Notification/CoreNotifier.php',
         'OC\\Core\\ResponseDefinitions' => __DIR__ . '/../../..' . '/core/ResponseDefinitions.php',
         'OC\\Core\\Service\\LoginFlowV2Service' => __DIR__ . '/../../..' . '/core/Service/LoginFlowV2Service.php',
@@ -2016,6 +2024,7 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OC\\Updater\\Exceptions\\ReleaseMetadataException' => __DIR__ . '/../../..' . '/lib/private/Updater/Exceptions/ReleaseMetadataException.php',
         'OC\\Updater\\ReleaseMetadata' => __DIR__ . '/../../..' . '/lib/private/Updater/ReleaseMetadata.php',
         'OC\\Updater\\VersionCheck' => __DIR__ . '/../../..' . '/lib/private/Updater/VersionCheck.php',
+        'OC\\UserPreferences' => __DIR__ . '/../../..' . '/lib/private/UserPreferences.php',
         'OC\\UserStatus\\ISettableProvider' => __DIR__ . '/../../..' . '/lib/private/UserStatus/ISettableProvider.php',
         'OC\\UserStatus\\Manager' => __DIR__ . '/../../..' . '/lib/private/UserStatus/Manager.php',
         'OC\\User\\AvailabilityCoordinator' => __DIR__ . '/../../..' . '/lib/private/User/AvailabilityCoordinator.php',
diff --git a/lib/private/Server.php b/lib/private/Server.php
index 01d5bdac0b66f..848b81aa07dff 100644
--- a/lib/private/Server.php
+++ b/lib/private/Server.php
@@ -238,6 +238,7 @@
 use OCP\User\Events\UserLoggedInWithCookieEvent;
 use OCP\User\Events\UserLoggedOutEvent;
 use OCP\User\IAvailabilityCoordinator;
+use OCP\UserPreferences\IUserPreferences;
 use Psr\Container\ContainerExceptionInterface;
 use Psr\Container\ContainerInterface;
 use Psr\Log\LoggerInterface;
@@ -606,6 +607,7 @@ public function __construct($webRoot, \OC\Config $config) {
 		/** @deprecated 19.0.0 */
 		$this->registerDeprecatedAlias('AppConfig', \OC\AppConfig::class);
 		$this->registerAlias(IAppConfig::class, \OC\AppConfig::class);
+		$this->registerAlias(IUserPreferences::class, \OC\UserPreferences::class);
 
 		$this->registerService(IFactory::class, function (Server $c) {
 			return new \OC\L10N\Factory(
diff --git a/lib/private/UserPreferences.php b/lib/private/UserPreferences.php
new file mode 100644
index 0000000000000..34df58c090d68
--- /dev/null
+++ b/lib/private/UserPreferences.php
@@ -0,0 +1,1483 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OC;
+
+use InvalidArgumentException;
+use JsonException;
+use OCP\DB\Exception as DBException;
+use OCP\DB\IResult;
+use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\IConfig;
+use OCP\IDBConnection;
+use OCP\Security\ICrypto;
+use OCP\UserPreferences\Exceptions\IncorrectTypeException;
+use OCP\UserPreferences\Exceptions\TypeConflictException;
+use OCP\UserPreferences\Exceptions\UnknownKeyException;
+use OCP\UserPreferences\IUserPreferences;
+use OCP\UserPreferences\ValueType;
+use Psr\Log\LoggerInterface;
+use ValueError;
+
+/**
+ * This class provides an easy way for apps to store user preferences in the
+ * database.
+ * Supports **lazy loading**
+ *
+ * ### What is lazy loading ?
+ * In order to avoid loading useless user preferences into memory for each request,
+ * only non-lazy values are now loaded.
+ *
+ * Once a value that is lazy is requested, all lazy values will be loaded.
+ *
+ * Similarly, some methods from this class are marked with a warning about ignoring
+ * lazy loading. Use them wisely and only on parts of the code that are called
+ * during specific requests or actions to avoid loading the lazy values all the time.
+ *
+ * @since 31.0.0
+ */
+class UserPreferences implements IUserPreferences {
+	private const USER_MAX_LENGTH = 64;
+	private const APP_MAX_LENGTH = 32;
+	private const KEY_MAX_LENGTH = 64;
+	private const ENCRYPTION_PREFIX = '$UserPreferencesEncryption$';
+	private const ENCRYPTION_PREFIX_LENGTH = 27; // strlen(self::ENCRYPTION_PREFIX)
+
+	/** @var array<string, array<string, array<string, mixed>>> ['user_id' => ['app_id' => ['key' => 'value']]] */
+	private array $fastCache = [];   // cache for normal preference keys
+	/** @var array<string, array<string, array<string, mixed>>> ['user_id' => ['app_id' => ['key' => 'value']]] */
+	private array $lazyCache = [];   // cache for lazy preference keys
+	/** @var array<string, array<string, array<string, int>>> ['user_id' => ['app_id' => ['key' => bitflag]]] */
+	private array $valueTypes = [];  // type for all preference values
+	/** @var array<string, boolean> ['user_id' => bool] */
+	private array $fastLoaded = [];
+	/** @var array<string, boolean> ['user_id' => bool] */
+	private array $lazyLoaded = [];
+
+	public function __construct(
+		protected IDBConnection $connection,
+		protected LoggerInterface $logger,
+		protected ICrypto $crypto,
+	) {
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $appId optional id of app
+	 *
+	 * @return string[] list of userIds
+	 * @since 31.0.0
+	 */
+	public function getUserIds(string $appId = ''): array {
+		$this->assertParams(app: $appId, allowEmptyUser: true, allowEmptyApp: true);
+
+		$qb = $this->connection->getQueryBuilder();
+		$qb->from('preferences');
+		$qb->select('userid');
+		$qb->groupBy('userid');
+		if ($appId !== '') {
+			$qb->where($qb->expr()->eq('app_id', $qb->createNamedParameter($appId)));
+		}
+
+		$result = $qb->executeQuery();
+		$rows = $result->fetchAll();
+		$userIds = [];
+		foreach ($rows as $row) {
+			$userIds[] = $row['userid'];
+		}
+
+		return $userIds;
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @return string[] list of app ids
+	 * @since 31.0.0
+	 */
+	public function getApps(string $userId): array {
+		$this->assertParams($userId, allowEmptyApp: true);
+		$this->loadPreferencesAll($userId);
+		$apps = array_merge(array_keys($this->fastCache[$userId]), array_keys($this->lazyCache[$userId]));
+		sort($apps);
+
+		return array_values(array_unique($apps));
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 *
+	 * @return string[] list of stored preference keys
+	 * @since 31.0.0
+	 */
+	public function getKeys(string $userId, string $app): array {
+		$this->assertParams($userId, $app);
+		$this->loadPreferencesAll($userId);
+		$keys = array_merge(array_keys($this->fastCache[$userId][$app] ?? []), array_keys($this->lazyCache[$userId][$app] ?? []));
+		sort($keys);
+
+		return array_values(array_unique($keys));
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param bool|null $lazy TRUE to search within lazy loaded preferences, NULL to search within all preferences
+	 *
+	 * @return bool TRUE if key exists
+	 * @since 31.0.0
+	 */
+	public function hasKey(string $userId, string $app, string $key, ?bool $lazy = false): bool {
+		$this->assertParams($userId, $app, $key);
+		$this->loadPreferences($userId, $lazy);
+
+		if ($lazy === null) {
+			$appCache = $this->getAllValues($userId, $app);
+			return isset($appCache[$key]);
+		}
+
+		if ($lazy) {
+			return isset($this->lazyCache[$userId][$app][$key]);
+		}
+
+		return isset($this->fastCache[$userId][$app][$key]);
+	}
+
+	/**
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param bool|null $lazy TRUE to search within lazy loaded preferences, NULL to search within all preferences
+	 *
+	 * @return bool
+	 * @throws UnknownKeyException if preference key is not known
+	 * @since 29.0.0
+	 */
+	public function isSensitive(string $userId, string $app, string $key, ?bool $lazy = false): bool {
+		$this->assertParams($userId, $app, $key);
+		$this->loadPreferences($userId, $lazy);
+
+		if (!isset($this->valueTypes[$userId][$app][$key])) {
+			throw new UnknownKeyException('unknown preference key');
+		}
+
+		return $this->isTyped(ValueType::SENSITIVE, $this->valueTypes[$userId][$app][$key]);
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app if of the app
+	 * @param string $key preference key
+	 *
+	 * @return bool TRUE if preference is lazy loaded
+	 * @throws UnknownKeyException if preference key is not known
+	 * @see IUserPreferences for details about lazy loading
+	 * @since 29.0.0
+	 */
+	public function isLazy(string $userId, string $app, string $key): bool {
+		// there is a huge probability the non-lazy preferences are already loaded
+		if ($this->hasKey($userId, $app, $key, false)) {
+			return false;
+		}
+
+		// key not found, we search in the lazy preferences
+		if ($this->hasKey($userId, $app, $key, true)) {
+			return true;
+		}
+
+		throw new UnknownKeyException('unknown preference key');
+	}
+
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $prefix preference keys prefix to search
+	 * @param bool $filtered TRUE to hide sensitive preference values. Value are replaced by {@see IConfig::SENSITIVE_VALUE}
+	 *
+	 * @return array<string, string|int|float|bool|array> [key => value]
+	 * @since 31.0.0
+	 */
+	public function getAllValues(string $userId, string $app, string $prefix = '', bool $filtered = false): array {
+		$this->assertParams($userId, $app, $prefix);
+		// if we want to filter values, we need to get sensitivity
+		$this->loadPreferencesAll($userId);
+		// array_merge() will remove numeric keys (here preference keys), so addition arrays instead
+		$values = $this->formatAppValues($userId, $app, ($this->fastCache[$userId][$app] ?? []) + ($this->lazyCache[$userId][$app] ?? []));
+		$values = array_filter(
+			$values,
+			function (string $key) use ($prefix): bool {
+				return str_starts_with($key, $prefix); // filter values based on $prefix
+			}, ARRAY_FILTER_USE_KEY
+		);
+
+		if (!$filtered) {
+			return $values;
+		}
+
+		$result = [];
+		foreach ($values as $key => $value) {
+			$result[$key] = $this->isTyped(ValueType::SENSITIVE, $this->valueTypes[$userId][$app][$key] ?? 0) ? IConfig::SENSITIVE_VALUE : $value;
+		}
+
+		return $result;
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $key preference key
+	 * @param bool $lazy search within lazy loaded preferences
+	 * @param int|null $typedAs enforce type for the returned values ({@see ValueType::STRING} and others)
+	 *
+	 * @return array<string, string|int|float|bool|array> [appId => value]
+	 * @since 31.0.0
+	 */
+	public function searchValuesByApps(string $userId, string $key, bool $lazy = false, ?ValueType $typedAs = null): array {
+		$this->assertParams($userId, '', $key, allowEmptyApp: true);
+		$this->loadPreferences($userId, $lazy);
+
+		/** @var array<array-key, array<array-key, mixed>> $cache */
+		if ($lazy) {
+			$cache = $this->lazyCache[$userId];
+		} else {
+			$cache = $this->fastCache[$userId];
+		}
+
+		$values = [];
+		foreach (array_keys($cache) as $app) {
+			if (isset($cache[$app][$key])) {
+				$value = $cache[$app][$key];
+				try {
+					$value = $this->convertTypedValue($value, $typedAs ?? $this->getValueType($userId, (string)$app, $key, $lazy));
+				} catch (IncorrectTypeException|UnknownKeyException) {
+				}
+				$values[$app] = $value;
+			}
+		}
+
+		return $values;
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param ValueType|null $typedAs enforce type for the returned values
+	 * @param array|null $userIds limit to a list of user ids
+	 *
+	 * @return array<string, string|int|float|bool|array> [userId => value]
+	 * @since 31.0.0
+	 */
+	public function searchValuesByUsers(
+		string $app,
+		string $key,
+		?ValueType $typedAs = null,
+		?array $userIds = null
+	): array {
+		$this->assertParams('', $app, $key, allowEmptyUser: true);
+
+		$qb = $this->connection->getQueryBuilder();
+		$qb->select('userid', 'configvalue', 'type')
+		   ->from('preferences')
+		   ->where($qb->expr()->eq('appid', $qb->createNamedParameter($app)))
+		   ->andWhere($qb->expr()->eq('configkey', $qb->createNamedParameter($key)));
+
+		$values = [];
+		// this nested function will execute current Query and store result within $values.
+		$executeAndStoreValue = function(IQueryBuilder $qb) use (&$values, $typedAs): IResult {
+			$result = $qb->executeQuery();
+			while ($row = $result->fetch()) {
+				$value = $row['configvalue'];
+				try {
+					$value = $this->convertTypedValue($value, $typedAs ?? $this->extractValueType($row['type']));
+				} catch (IncorrectTypeException) {
+				}
+				$values[$row['userid']] = $value;
+			}
+			return $result;
+		};
+
+		// if no userIds to filter, we execute query as it is and returns all values ...
+		if ($userIds === null) {
+			$result = $executeAndStoreValue($qb);
+			$result->closeCursor();
+			return $values;
+		}
+
+		// if userIds to filter, we chunk the list and execute the same query multiple times until we get all values
+		$result = null;
+		$qb->andWhere($qb->expr()->in('userid', $qb->createParameter('userIds')));
+		foreach (array_chunk($userIds, 50, true) as $chunk) {
+			$qb->setParameter('userIds', $chunk, IQueryBuilder::PARAM_STR_ARRAY);
+			$result = $executeAndStoreValue($qb);
+		}
+		$result?->closeCursor();
+
+		return $values;
+	}
+
+	/**
+	 * Get the preference value as string.
+	 * If the value does not exist the given default will be returned.
+	 *
+	 * Set lazy to `null` to ignore it and get the value from either source.
+	 *
+	 * **WARNING:** Method is internal and **SHOULD** not be used, as it is better to get the value with a type.
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param string $default preference value
+	 * @param null|bool $lazy get preference as lazy loaded or not. can be NULL
+	 *
+	 * @return string the value or $default
+	 * @throws TypeConflictException
+	 * @internal
+	 * @since 31.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 * @see getValueString()
+	 * @see getValueInt()
+	 * @see getValueFloat()
+	 * @see getValueBool()
+	 * @see getValueArray()
+	 */
+	public function getValueMixed(
+		string $userId,
+		string $app,
+		string $key,
+		string $default = '',
+		?bool $lazy = false
+	): string {
+		try {
+			$lazy = ($lazy === null) ? $this->isLazy($userId, $app, $key) : $lazy;
+		} catch (UnknownKeyException) {
+			return $default;
+		}
+
+		return $this->getTypedValue(
+			$userId,
+			$app,
+			$key,
+			$default,
+			$lazy,
+			ValueType::MIXED
+		);
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param string $default default value
+	 * @param bool $lazy search within lazy loaded preferences
+	 *
+	 * @return string stored preference value or $default if not set in database
+	 * @throws InvalidArgumentException if one of the argument format is invalid
+	 * @throws TypeConflictException in case of conflict with the value type set in database
+	 * @since 31.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 */
+	public function getValueString(
+		string $userId,
+		string $app,
+		string $key,
+		string $default = '',
+		bool $lazy = false
+	): string {
+		return $this->getTypedValue($userId, $app, $key, $default, $lazy, ValueType::STRING);
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param int $default default value
+	 * @param bool $lazy search within lazy loaded preferences
+	 *
+	 * @return int stored preference value or $default if not set in database
+	 * @throws InvalidArgumentException if one of the argument format is invalid
+	 * @throws TypeConflictException in case of conflict with the value type set in database
+	 * @since 31.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 */
+	public function getValueInt(
+		string $userId,
+		string $app,
+		string $key,
+		int $default = 0,
+		bool $lazy = false
+	): int {
+		return (int)$this->getTypedValue($userId, $app, $key, (string)$default, $lazy, ValueType::INT);
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param float $default default value
+	 * @param bool $lazy search within lazy loaded preferences
+	 *
+	 * @return float stored preference value or $default if not set in database
+	 * @throws InvalidArgumentException if one of the argument format is invalid
+	 * @throws TypeConflictException in case of conflict with the value type set in database
+	 * @since 29.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 */
+	public function getValueFloat(
+		string $userId,
+		string $app,
+		string $key,
+		float $default = 0,
+		bool $lazy = false
+	): float {
+		return (float)$this->getTypedValue($userId, $app, $key, (string)$default, $lazy, ValueType::FLOAT);
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param bool $default default value
+	 * @param bool $lazy search within lazy loaded preferences
+	 *
+	 * @return bool stored preference value or $default if not set in database
+	 * @throws InvalidArgumentException if one of the argument format is invalid
+	 * @throws TypeConflictException in case of conflict with the value type set in database
+	 * @since 29.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 */
+	public function getValueBool(
+		string $userId,
+		string $app,
+		string $key,
+		bool $default = false,
+		bool $lazy = false
+	): bool {
+		$b = strtolower($this->getTypedValue($userId, $app, $key, $default ? 'true' : 'false', $lazy, ValueType::BOOL));
+		return in_array($b, ['1', 'true', 'yes', 'on']);
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param array $default default value
+	 * @param bool $lazy search within lazy loaded preferences
+	 *
+	 * @return array stored preference value or $default if not set in database
+	 * @throws InvalidArgumentException if one of the argument format is invalid
+	 * @throws TypeConflictException in case of conflict with the value type set in database
+	 * @since 29.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 */
+	public function getValueArray(
+		string $userId,
+		string $app,
+		string $key,
+		array $default = [],
+		bool $lazy = false
+	): array {
+		try {
+			$defaultJson = json_encode($default, JSON_THROW_ON_ERROR);
+			$value = json_decode($this->getTypedValue($userId, $app, $key, $defaultJson, $lazy, ValueType::ARRAY), true, flags: JSON_THROW_ON_ERROR);
+
+			return is_array($value) ? $value : [];
+		} catch (JsonException) {
+			return [];
+		}
+	}
+
+	/**
+	 * @param string $userId
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param string $default default value
+	 * @param bool $lazy search within lazy loaded preferences
+	 * @param ValueType $type value type
+	 *
+	 * @return string
+	 * @throws TypeConflictException if type from database is not VALUE_MIXED and different from the requested one
+	 */
+	private function getTypedValue(
+		string $userId,
+		string $app,
+		string $key,
+		string $default,
+		bool $lazy,
+		ValueType $type
+	): string {
+		$this->assertParams($userId, $app, $key, valueType: $type);
+		$this->loadPreferences($userId, $lazy);
+
+		/**
+		 * We ignore check if mixed type is requested.
+		 * If type of stored value is set as mixed, we don't filter.
+		 * If type of stored value is defined, we compare with the one requested.
+		 */
+		$knownType = $this->valueTypes[$userId][$app][$key] ?? 0;
+		if (!$this->isTyped(ValueType::MIXED, $type->value)
+			&& $knownType > 0
+			&& !$this->isTyped(ValueType::MIXED, $knownType)
+			&& !$this->isTyped($type, $knownType)) {
+			$this->logger->warning('conflict with value type from database', ['app' => $app, 'key' => $key, 'type' => $type, 'knownType' => $knownType]);
+			throw new TypeConflictException('conflict with value type from database');
+		}
+
+		/**
+		 * - the pair $app/$key cannot exist in both array,
+		 * - we should still return an existing non-lazy value even if current method
+		 *   is called with $lazy is true
+		 *
+		 * This way, lazyCache will be empty until the load for lazy preferences value is requested.
+		 */
+		if (isset($this->lazyCache[$userId][$app][$key])) {
+			$value = $this->lazyCache[$userId][$app][$key];
+		} elseif (isset($this->fastCache[$userId][$app][$key])) {
+			$value = $this->fastCache[$userId][$app][$key];
+		} else {
+			return $default;
+		}
+
+		$sensitive = $this->isTyped(ValueType::SENSITIVE, $knownType);
+		if ($sensitive && str_starts_with($value, self::ENCRYPTION_PREFIX)) {
+			// Only decrypt values that are stored encrypted
+			$value = $this->crypto->decrypt(substr($value, self::ENCRYPTION_PREFIX_LENGTH));
+		}
+
+		return $value;
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 *
+	 * @return ValueType type of the value
+	 * @throws UnknownKeyException if preference key is not known
+	 * @throws IncorrectTypeException if preferences value type is not known
+	 * @since 31.0.0
+	 */
+	public function getValueType(string $userId, string $app, string $key, ?bool $lazy = null): ValueType {
+		$this->assertParams($userId, $app, $key);
+		$this->loadPreferences($userId, $lazy);
+
+		if (!isset($this->valueTypes[$userId][$app][$key])) {
+			throw new UnknownKeyException('unknown preference key');
+		}
+
+		return $this->extractValueType($this->valueTypes[$userId][$app][$key]);
+	}
+
+	/**
+	 * convert bitflag from value type to ValueType
+	 *
+	 * @param int $type
+	 *
+	 * @return ValueType
+	 * @throws IncorrectTypeException
+	 */
+	private function extractValueType(int $type): ValueType {
+		$type &= ~ValueType::SENSITIVE->value;
+
+		try {
+			return ValueType::from($type);
+		} catch (ValueError) {
+			throw new IncorrectTypeException('invalid value type');
+		}
+	}
+
+	/**
+	 * Store a preference key and its value in database as VALUE_MIXED
+	 *
+	 * **WARNING:** Method is internal and **MUST** not be used as it is best to set a real value type
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param string $value preference value
+	 * @param bool $lazy set preference as lazy loaded
+	 * @param bool $sensitive if TRUE value will be hidden when listing preference values.
+	 *
+	 * @return bool TRUE if value was different, therefor updated in database
+	 * @throws TypeConflictException if type from database is not VALUE_MIXED
+	 * @internal
+	 * @since 29.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 * @see setValueString()
+	 * @see setValueInt()
+	 * @see setValueFloat()
+	 * @see setValueBool()
+	 * @see setValueArray()
+	 */
+	public function setValueMixed(
+		string $userId,
+		string $app,
+		string $key,
+		string $value,
+		bool $lazy = false,
+		bool $sensitive = false
+	): bool {
+		return $this->setTypedValue(
+			$userId,
+			$app,
+			$key,
+			$value,
+			$lazy,
+			$sensitive,
+			ValueType::MIXED
+		);
+	}
+
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param string $value preference value
+	 * @param bool $lazy set preference as lazy loaded
+	 * @param bool $sensitive if TRUE value will be hidden when listing preference values.
+	 *
+	 * @return bool TRUE if value was different, therefor updated in database
+	 * @throws TypeConflictException if type from database is not VALUE_MIXED and different from the requested one
+	 * @since 29.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 */
+	public function setValueString(
+		string $userId,
+		string $app,
+		string $key,
+		string $value,
+		bool $lazy = false,
+		bool $sensitive = false
+	): bool {
+		return $this->setTypedValue(
+			$userId,
+			$app,
+			$key,
+			$value,
+			$lazy,
+			$sensitive,
+			ValueType::STRING
+		);
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param int $value preference value
+	 * @param bool $lazy set preference as lazy loaded
+	 * @param bool $sensitive if TRUE value will be hidden when listing preference values.
+	 *
+	 * @return bool TRUE if value was different, therefor updated in database
+	 * @throws TypeConflictException if type from database is not VALUE_MIXED and different from the requested one
+	 * @since 29.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 */
+	public function setValueInt(
+		string $userId,
+		string $app,
+		string $key,
+		int $value,
+		bool $lazy = false,
+		bool $sensitive = false
+	): bool {
+		if ($value > 2000000000) {
+			$this->logger->debug('You are trying to store an integer value around/above 2,147,483,647. This is a reminder that reaching this theoretical limit on 32 bits system will throw an exception.');
+		}
+
+		return $this->setTypedValue(
+			$userId,
+			$app,
+			$key,
+			(string)$value,
+			$lazy,
+			$sensitive,
+			ValueType::INT
+		);
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param float $value preference value
+	 * @param bool $lazy set preference as lazy loaded
+	 * @param bool $sensitive if TRUE value will be hidden when listing preference values.
+	 *
+	 * @return bool TRUE if value was different, therefor updated in database
+	 * @throws TypeConflictException if type from database is not VALUE_MIXED and different from the requested one
+	 * @since 29.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 */
+	public function setValueFloat(
+		string $userId,
+		string $app,
+		string $key,
+		float $value,
+		bool $lazy = false,
+		bool $sensitive = false
+	): bool {
+		return $this->setTypedValue(
+			$userId,
+			$app,
+			$key,
+			(string)$value,
+			$lazy,
+			$sensitive,
+			ValueType::FLOAT
+		);
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param bool $value preference value
+	 * @param bool $lazy set preference as lazy loaded
+	 *
+	 * @return bool TRUE if value was different, therefor updated in database
+	 * @throws TypeConflictException if type from database is not VALUE_MIXED and different from the requested one
+	 * @since 29.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 */
+	public function setValueBool(
+		string $userId,
+		string $app,
+		string $key,
+		bool $value,
+		bool $lazy = false
+	): bool {
+		return $this->setTypedValue(
+			$userId,
+			$app,
+			$key,
+			($value) ? '1' : '0',
+			$lazy,
+			false,
+			ValueType::BOOL
+		);
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param array $value preference value
+	 * @param bool $lazy set preference as lazy loaded
+	 * @param bool $sensitive if TRUE value will be hidden when listing preference values.
+	 *
+	 * @return bool TRUE if value was different, therefor updated in database
+	 * @throws TypeConflictException if type from database is not VALUE_MIXED and different from the requested one
+	 * @throws JsonException
+	 * @since 29.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 */
+	public function setValueArray(
+		string $userId,
+		string $app,
+		string $key,
+		array $value,
+		bool $lazy = false,
+		bool $sensitive = false
+	): bool {
+		try {
+			return $this->setTypedValue(
+				$userId,
+				$app,
+				$key,
+				json_encode($value, JSON_THROW_ON_ERROR),
+				$lazy,
+				$sensitive,
+				ValueType::ARRAY
+			);
+		} catch (JsonException $e) {
+			$this->logger->warning('could not setValueArray', ['app' => $app, 'key' => $key, 'exception' => $e]);
+			throw $e;
+		}
+	}
+
+	/**
+	 * Store a preference key and its value in database
+	 *
+	 * If preference key is already known with the exact same preference value and same sensitive/lazy status, the
+	 * database is not updated. If preference value was previously stored as sensitive, status will not be
+	 * altered.
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param string $value preference value
+	 * @param bool $lazy preferences set as lazy loaded
+	 * @param ValueType $type value type
+	 *
+	 * @return bool TRUE if value was updated in database
+	 * @throws TypeConflictException if type from database is not VALUE_MIXED and different from the requested one
+	 * @see IUserPreferences for explanation about lazy loading
+	 */
+	private function setTypedValue(
+		string $userId,
+		string $app,
+		string $key,
+		string $value,
+		bool $lazy,
+		bool $sensitive,
+		ValueType $type
+	): bool {
+		$this->assertParams($userId, $app, $key, valueType: $type);
+		$this->loadPreferences($userId, $lazy);
+
+		$inserted = $refreshCache = false;
+		$origValue = $value;
+		$typeValue = $type->value;
+		if ($sensitive || ($this->hasKey($userId, $app, $key, $lazy) && $this->isSensitive($userId, $app, $key, $lazy))) {
+			$value = self::ENCRYPTION_PREFIX . $this->crypto->encrypt($value);
+			$typeValue = $typeValue | ValueType::SENSITIVE->value;
+		}
+
+		if ($this->hasKey($userId, $app, $key, $lazy)) {
+			/**
+			 * no update if key is already known with set lazy status and value is
+			 * not different, unless sensitivity is switched from false to true.
+			 */
+			if ($origValue === $this->getTypedValue($userId, $app, $key, $value, $lazy, $type)
+				&& (!$sensitive || $this->isSensitive($userId, $app, $key, $lazy))) {
+				return false;
+			}
+		} else {
+			/**
+			 * if key is not known yet, we try to insert.
+			 * It might fail if the key exists with a different lazy flag.
+			 */
+			try {
+				$insert = $this->connection->getQueryBuilder();
+				$insert->insert('preferences')
+					   ->setValue('userid', $insert->createNamedParameter($userId))
+					   ->setValue('appid', $insert->createNamedParameter($app))
+					   ->setValue('lazy', $insert->createNamedParameter(($lazy) ? 1 : 0, IQueryBuilder::PARAM_INT))
+					   ->setValue('type', $insert->createNamedParameter($typeValue, IQueryBuilder::PARAM_INT))
+					   ->setValue('configkey', $insert->createNamedParameter($key))
+					   ->setValue('configvalue', $insert->createNamedParameter($value));
+				$insert->executeStatement();
+				$inserted = true;
+			} catch (DBException $e) {
+				if ($e->getReason() !== DBException::REASON_UNIQUE_CONSTRAINT_VIOLATION) {
+					throw $e; // TODO: throw exception or just log and returns false !?
+				}
+			}
+		}
+
+		/**
+		 * We cannot insert a new row, meaning we need to update an already existing one
+		 */
+		if (!$inserted) {
+			$currType = $this->valueTypes[$userId][$app][$key] ?? 0;
+			if ($currType === 0) { // this might happen when switching lazy loading status
+				$this->loadPreferencesAll($userId);
+				$currType = $this->valueTypes[$userId][$app][$key] ?? 0;
+			}
+
+			/**
+			 * This should only happen during the upgrade process from 28 to 29.
+			 * We only log a warning and set it to VALUE_MIXED.
+			 */
+			if ($currType === 0) {
+				$this->logger->warning('Value type is set to zero (0) in database. This is fine only during the upgrade process from 28 to 29.', ['app' => $app, 'key' => $key]);
+				$currType = ValueType::MIXED->value;
+			}
+
+//			if ($type->isSensitive()) {}
+
+			/**
+			 * we only accept a different type from the one stored in database
+			 * if the one stored in database is not-defined (VALUE_MIXED)
+			 */
+			if (!$this->isTyped(ValueType::MIXED, $currType) &&
+				($type->value | ValueType::SENSITIVE->value) !== ($currType | ValueType::SENSITIVE->value)) {
+				try {
+					$currType = $this->extractValueType($currType)->getDefinition();
+					$type = $type->getDefinition();
+				} catch (IncorrectTypeException) {
+					$type = $type->value;
+				}
+				throw new TypeConflictException('conflict between new type (' . $type . ') and old type (' . $currType . ')');
+			}
+
+			// we fix $type if the stored value, or the new value as it might be changed, is set as sensitive
+//			if ($sensitive || $this->isTyped(ValueType::SENSITIVE, $currType)) {
+//				$type |= ValueType::SENSITIVE;
+//			}
+
+			if ($lazy !== $this->isLazy($userId, $app, $key)) {
+				$refreshCache = true;
+			}
+
+			$update = $this->connection->getQueryBuilder();
+			$update->update('preferences')
+				   ->set('configvalue', $update->createNamedParameter($value))
+				   ->set('lazy', $update->createNamedParameter(($lazy) ? 1 : 0, IQueryBuilder::PARAM_INT))
+				   ->set('type', $update->createNamedParameter($typeValue, IQueryBuilder::PARAM_INT))
+				   ->where($update->expr()->eq('userid', $update->createNamedParameter($userId)))
+				   ->andWhere($update->expr()->eq('appid', $update->createNamedParameter($app)))
+				   ->andWhere($update->expr()->eq('configkey', $update->createNamedParameter($key)));
+
+			$update->executeStatement();
+		}
+
+		if ($refreshCache) {
+			$this->clearCache($userId);
+			return true;
+		}
+
+		// update local cache
+		if ($lazy) {
+			$this->lazyCache[$userId][$app][$key] = $value;
+		} else {
+			$this->fastCache[$userId][$app][$key] = $value;
+		}
+		$this->valueTypes[$userId][$app][$key] = $typeValue;
+
+		return true;
+	}
+
+	/**
+	 * Change the type of preference value.
+	 *
+	 * **WARNING:** Method is internal and **MUST** not be used as it may break things.
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param ValueType $type value type
+	 *
+	 * @return bool TRUE if database update were necessary
+	 * @throws UnknownKeyException if $key is now known in database
+	 * @throws IncorrectTypeException if $type is not valid
+	 * @internal
+	 * @since 31.0.0
+	 */
+	public function updateType(string $userId, string $app, string $key, ValueType $type = ValueType::MIXED): bool {
+		$this->assertParams($userId, $app, $key, valueType: $type);
+		$this->loadPreferencesAll($userId);
+		$this->isLazy($userId, $app, $key); // confirm key exists
+		$typeValue = $type->value;
+
+		$currType = $this->valueTypes[$userId][$app][$key];
+		if (($typeValue | ValueType::SENSITIVE->value) === ($currType | ValueType::SENSITIVE->value)) {
+			return false;
+		}
+
+		// we complete with sensitive flag if the stored value is set as sensitive
+		if ($this->isTyped(ValueType::SENSITIVE, $currType)) {
+			$typeValue = $typeValue | ValueType::SENSITIVE->value;
+		}
+
+		$update = $this->connection->getQueryBuilder();
+		$update->update('preferences')
+			   ->set('type', $update->createNamedParameter($typeValue, IQueryBuilder::PARAM_INT))
+			   ->where($update->expr()->eq('userid', $update->createNamedParameter($userId)))
+			   ->andWhere($update->expr()->eq('appid', $update->createNamedParameter($app)))
+			   ->andWhere($update->expr()->eq('configkey', $update->createNamedParameter($key)));
+		$update->executeStatement();
+		$this->valueTypes[$userId][$app][$key] = $typeValue;
+
+		return true;
+	}
+
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param bool $sensitive TRUE to set as sensitive, FALSE to unset
+	 *
+	 * @return bool TRUE if entry was found in database and an update was necessary
+	 * @since 31.0.0
+	 */
+	public function updateSensitive(string $userId, string $app, string $key, bool $sensitive): bool {
+		$this->assertParams($userId, $app, $key);
+		$this->loadPreferencesAll($userId);
+
+		try {
+			if ($sensitive === $this->isSensitive($userId, $app, $key, null)) {
+				return false;
+			}
+		} catch (UnknownKeyException $e) {
+			return false;
+		}
+
+		$lazy = $this->isLazy($userId, $app, $key);
+		if ($lazy) {
+			$cache = $this->lazyCache;
+		} else {
+			$cache = $this->fastCache;
+		}
+
+		if (!isset($cache[$userId][$app][$key])) {
+			throw new UnknownKeyException('unknown preference key');
+		}
+
+		/**
+		 * type returned by getValueType() is already cleaned from sensitive flag
+		 * we just need to update it based on $sensitive and store it in database
+		 */
+		$typeValue = $this->getValueType($userId, $app, $key)->value;
+		$value = $cache[$userId][$app][$key];
+		if ($sensitive) {
+			$typeValue |= ValueType::SENSITIVE->value;
+			$value = self::ENCRYPTION_PREFIX . $this->crypto->encrypt($value);
+		} else {
+			$value = $this->crypto->decrypt(substr($value, self::ENCRYPTION_PREFIX_LENGTH));
+		}
+
+		$update = $this->connection->getQueryBuilder();
+		$update->update('preferences')
+			   ->set('type', $update->createNamedParameter($typeValue, IQueryBuilder::PARAM_INT))
+			   ->set('configvalue', $update->createNamedParameter($value))
+			   ->where($update->expr()->eq('userid', $update->createNamedParameter($userId)))
+			   ->andWhere($update->expr()->eq('appid', $update->createNamedParameter($app)))
+			   ->andWhere($update->expr()->eq('configkey', $update->createNamedParameter($key)));
+		$update->executeStatement();
+
+		$this->valueTypes[$userId][$app][$key] = $typeValue;
+
+		return true;
+	}
+
+	public function updateGlobalSensitive(string $app, string $key, bool $sensitive): void {
+
+	}
+
+
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param bool $lazy TRUE to set as lazy loaded, FALSE to unset
+	 *
+	 * @return bool TRUE if entry was found in database and an update was necessary
+	 * @since 31.0.0
+	 */
+	public function updateLazy(string $userId, string $app, string $key, bool $lazy): bool {
+		$this->assertParams($userId, $app, $key);
+		$this->loadPreferencesAll($userId);
+
+		try {
+			if ($lazy === $this->isLazy($userId, $app, $key)) {
+				return false;
+			}
+		} catch (UnknownKeyException) {
+			return false;
+		}
+
+		$update = $this->connection->getQueryBuilder();
+		$update->update('preferences')
+			   ->set('lazy', $update->createNamedParameter($lazy ? 1 : 0, IQueryBuilder::PARAM_INT))
+			   ->where($update->expr()->eq('userid', $update->createNamedParameter($userId)))
+			   ->andWhere($update->expr()->eq('appid', $update->createNamedParameter($app)))
+			   ->andWhere($update->expr()->eq('configkey', $update->createNamedParameter($key)));
+		$update->executeStatement();
+
+		// At this point, it is a lot safer to clean cache
+		$this->clearCache($userId);
+
+		return true;
+	}
+
+	public function updateGlobalLazy(string $app, string $key, bool $lazy): void {
+
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 *
+	 * @return array
+	 * @throws UnknownKeyException if preference key is not known in database
+	 * @since 31.0.0
+	 */
+	public function getDetails(string $userId, string $app, string $key): array {
+		$this->assertParams($userId, $app, $key);
+		$this->loadPreferencesAll($userId);
+		$lazy = $this->isLazy($userId, $app, $key);
+
+		if ($lazy) {
+			$cache = $this->lazyCache[$userId];
+		} else {
+			$cache = $this->fastCache[$userId];
+		}
+
+		$type = $this->getValueType($userId, $app, $key);
+		try {
+			$typeString = $type->getDefinition();
+		} catch (IncorrectTypeException $e) {
+			$this->logger->warning('type stored in database is not correct', ['exception' => $e, 'type' => $type]);
+			$typeString = (string)$type->value;
+		}
+
+		if (!isset($cache[$app][$key])) {
+			throw new UnknownKeyException('unknown preference key');
+		}
+
+		$value = $cache[$app][$key];
+		$sensitive = $this->isSensitive($userId, $app, $key, null);
+		if ($sensitive && str_starts_with($value, self::ENCRYPTION_PREFIX)) {
+			$value = $this->crypto->decrypt(substr($value, self::ENCRYPTION_PREFIX_LENGTH));
+		}
+
+		return [
+			'userId' => $userId,
+			'app' => $app,
+			'key' => $key,
+			'value' => $value,
+			'type' => $type,
+			'lazy' => $lazy,
+			'typeString' => $typeString,
+			'sensitive' => $sensitive
+		];
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 *
+	 * @since 31.0.0
+	 */
+	public function deletePreference(string $userId, string $app, string $key): void {
+		$this->assertParams($userId, $app, $key);
+		$qb = $this->connection->getQueryBuilder();
+		$qb->delete('preferences')
+		   ->where($qb->expr()->eq('userid', $qb->createNamedParameter($userId)))
+		   ->andWhere($qb->expr()->eq('appid', $qb->createNamedParameter($app)))
+		   ->andWhere($qb->expr()->eq('configkey', $qb->createNamedParameter($key)));
+		$qb->executeStatement();
+
+		unset($this->lazyCache[$userId][$app][$key]);
+		unset($this->fastCache[$userId][$app][$key]);
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 *
+	 * @since 31.0.0
+	 */
+	public function deleteKey(string $app, string $key): void {
+		$this->assertParams('', $app, $key, allowEmptyUser: true);
+		$qb = $this->connection->getQueryBuilder();
+		$qb->delete('preferences')
+		   ->where($qb->expr()->eq('appid', $qb->createNamedParameter($app)))
+		   ->andWhere($qb->expr()->eq('configkey', $qb->createNamedParameter($key)));
+		$qb->executeStatement();
+
+		$this->clearCacheAll();
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $app id of the app
+	 *
+	 * @since 31.0.0
+	 */
+	public function deleteApp(string $app): void {
+		$this->assertParams('', $app, allowEmptyUser: true);
+		$qb = $this->connection->getQueryBuilder();
+		$qb->delete('preferences')
+		   ->where($qb->expr()->eq('appid', $qb->createNamedParameter($app)));
+		$qb->executeStatement();
+
+		$this->clearCacheAll();
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @param string $userId id of the user
+	 * @param bool $reload set to TRUE to refill cache instantly after clearing it.
+	 *
+	 * @since 31.0.0
+	 */
+	public function clearCache(string $userId, bool $reload = false): void {
+		$this->assertParams($userId, allowEmptyApp: true);
+		$this->lazyLoaded[$userId] = $this->fastLoaded[$userId] = false;
+		$this->lazyCache[$userId] = $this->fastCache[$userId] = $this->valueTypes[$userId] = [];
+
+		if (!$reload) {
+			return;
+		}
+
+		$this->loadPreferencesAll($userId);
+	}
+
+	/**
+	 * @inheritDoc
+	 *
+	 * @since 31.0.0
+	 */
+	public function clearCacheAll(): void {
+		$this->lazyLoaded = $this->fastLoaded = [];
+		$this->lazyCache = $this->fastCache = $this->valueTypes = [];
+	}
+
+
+	/**
+	 * For debug purpose.
+	 * Returns the cached data.
+	 *
+	 * @return array
+	 * @since 31.0.0
+	 * @internal
+	 */
+	public function statusCache(): array {
+		return [
+			'fastLoaded' => $this->fastLoaded,
+			'fastCache' => $this->fastCache,
+			'lazyLoaded' => $this->lazyLoaded,
+			'lazyCache' => $this->lazyCache,
+			'valueTypes' => $this->valueTypes,
+		];
+	}
+
+	/**
+	 * @param ValueType $needle bitflag to search
+	 * @param int $type known value
+	 *
+	 * @return bool TRUE if bitflag $needle is set in $type
+	 */
+	private function isTyped(ValueType $needle, int $type): bool {
+		return (($needle->value & $type) !== 0);
+	}
+
+	/**
+	 * Confirm the string set for app and key fit the database description
+	 *
+	 * @param string $userId
+	 * @param string $app assert $app fit in database
+	 * @param string $prefKey assert preference key fit in database
+	 * @param bool $allowEmptyUser
+	 * @param bool $allowEmptyApp $app can be empty string
+	 * @param ValueType|null $valueType assert value type is only one type
+	 */
+	private function assertParams(
+		string $userId = '',
+		string $app = '',
+		string $prefKey = '',
+		bool $allowEmptyUser = false,
+		bool $allowEmptyApp = false,
+		?ValueType $valueType = null
+	): void {
+		if (!$allowEmptyUser && $userId === '') {
+			throw new InvalidArgumentException('userId cannot be an empty string');
+		}
+		if (!$allowEmptyApp && $app === '') {
+			throw new InvalidArgumentException('app cannot be an empty string');
+		}
+		if (strlen($userId) > self::USER_MAX_LENGTH) {
+			throw new InvalidArgumentException('Value (' . $userId . ') for userId is too long (' . self::USER_MAX_LENGTH . ')');
+		}
+		if (strlen($app) > self::APP_MAX_LENGTH) {
+			throw new InvalidArgumentException('Value (' . $app . ') for app is too long (' . self::APP_MAX_LENGTH . ')');
+		}
+		if (strlen($prefKey) > self::KEY_MAX_LENGTH) {
+			throw new InvalidArgumentException('Value (' . $prefKey . ') for key is too long (' . self::KEY_MAX_LENGTH . ')');
+		}
+		if ($valueType !== null) {
+			$valueFlag = $valueType->value;
+			$valueFlag &= ~ValueType::SENSITIVE->value;
+			if (ValueType::tryFrom($valueFlag) === null) {
+				throw new InvalidArgumentException('Unknown value type');
+			}
+		}
+	}
+
+	private function loadPreferencesAll(string $userId): void {
+		$this->loadPreferences($userId, null);
+	}
+
+	/**
+	 * Load normal preferences or preferences set as lazy loaded
+	 *
+	 * @param bool|null $lazy set to TRUE to load preferences set as lazy loaded, set to NULL to load all preferences
+	 */
+	private function loadPreferences(string $userId, ?bool $lazy = false): void {
+		if ($this->isLoaded($userId, $lazy)) {
+			return;
+		}
+
+		if (($lazy ?? true) !== false) { // if lazy is null or true, we debug log
+			$this->logger->debug('The loading of lazy UserPreferences values have been requested', ['exception' => new \RuntimeException('ignorable exception')]);
+		}
+
+		$qb = $this->connection->getQueryBuilder();
+		$qb->from('preferences');
+		$qb->select('userid', 'appid', 'configkey', 'configvalue', 'type');
+		$qb->where($qb->expr()->eq('userid', $qb->createNamedParameter($userId)));
+
+		// we only need value from lazy when loadPreferences does not specify it
+		if ($lazy !== null) {
+			$qb->andWhere($qb->expr()->eq('lazy', $qb->createNamedParameter($lazy ? 1 : 0, IQueryBuilder::PARAM_INT)));
+		} else {
+			$qb->addSelect('lazy');
+		}
+
+		$result = $qb->executeQuery();
+		$rows = $result->fetchAll();
+		foreach ($rows as $row) {
+			if (($row['lazy'] ?? ($lazy ?? 0) ? 1 : 0) === 1) {
+				$this->lazyCache[$row['userid']][$row['appid']][$row['configkey']] = $row['configvalue'] ?? '';
+			} else {
+				$this->fastCache[$row['userid']][$row['appid']][$row['configkey']] = $row['configvalue'] ?? '';
+			}
+			$this->valueTypes[$row['userid']][$row['appid']][$row['configkey']] = (int)($row['type'] ?? 0);
+		}
+		$result->closeCursor();
+		$this->setAsLoaded($userId, $lazy);
+	}
+
+	/**
+	 * if $lazy is:
+	 *  - false: will returns true if fast preferences are loaded
+	 *  - true : will returns true if lazy preferences are loaded
+	 *  - null : will returns true if both preferences are loaded
+	 *
+	 * @param string $userId
+	 * @param bool $lazy
+	 *
+	 * @return bool
+	 */
+	private function isLoaded(string $userId, ?bool $lazy): bool {
+		if ($lazy === null) {
+			return ($this->lazyLoaded[$userId] ?? false) && ($this->fastLoaded[$userId] ?? false);
+		}
+
+		return $lazy ? $this->lazyLoaded[$userId] ?? false : $this->fastLoaded[$userId] ?? false;
+	}
+
+	/**
+	 * if $lazy is:
+	 * - false: set fast preferences as loaded
+	 * - true : set lazy preferences as loaded
+	 * - null : set both preferences as loaded
+	 *
+	 * @param string $userId
+	 * @param bool $lazy
+	 */
+	private function setAsLoaded(string $userId, ?bool $lazy): void {
+		if ($lazy === null) {
+			$this->fastLoaded[$userId] = $this->lazyLoaded[$userId] = true;
+			return;
+		}
+
+		if ($lazy) {
+			$this->lazyLoaded[$userId] = true;
+		} else {
+			$this->fastLoaded[$userId] = true;
+		}
+	}
+
+	/**
+	 * **Warning:** avoid default NULL value for $lazy as this will
+	 * load all lazy values from the database
+	 *
+	 * @param string $app
+	 * @param array<string, string> $values ['key' => 'value']
+	 * @param bool|null $lazy
+	 *
+	 * @return array<string, string|int|float|bool|array>
+	 */
+	private function formatAppValues(string $userId, string $app, array $values, ?bool $lazy = null): array {
+		foreach($values as $key => $value) {
+			try {
+				$type = $this->getValueType($userId, $app, $key, $lazy);
+			} catch (UnknownKeyException $e) {
+				continue;
+			}
+
+			$values[$key] = $this->convertTypedValue($value, $type);
+		}
+
+		return $values;
+	}
+
+	/**
+	 * convert string value to the expected type
+	 *
+	 * @param string $value
+	 * @param ValueType $type
+	 *
+	 * @return string|int|float|bool|array
+	 */
+	private function convertTypedValue(string $value, ValueType $type): string|int|float|bool|array {
+		switch ($type) {
+			case ValueType::INT:
+				return (int)$value;
+			case ValueType::FLOAT:
+				return (float)$value;
+			case ValueType::BOOL:
+				return in_array(strtolower($value), ['1', 'true', 'yes', 'on']);
+			case ValueType::ARRAY:
+				try {
+					return json_decode($value, true, flags: JSON_THROW_ON_ERROR);
+				} catch (JsonException) {
+					// ignoreable
+				}
+				break;
+		}
+		return $value;
+	}
+}
diff --git a/lib/public/UserPreferences/Exceptions/IncorrectTypeException.php b/lib/public/UserPreferences/Exceptions/IncorrectTypeException.php
new file mode 100644
index 0000000000000..5c8f83dee5efe
--- /dev/null
+++ b/lib/public/UserPreferences/Exceptions/IncorrectTypeException.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\UserPreferences\Exceptions;
+
+/**
+ * @since 31.0.0
+ */
+class IncorrectTypeException extends UserPreferencesException {
+}
diff --git a/lib/public/UserPreferences/Exceptions/TypeConflictException.php b/lib/public/UserPreferences/Exceptions/TypeConflictException.php
new file mode 100644
index 0000000000000..b67113fbba757
--- /dev/null
+++ b/lib/public/UserPreferences/Exceptions/TypeConflictException.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\UserPreferences\Exceptions;
+
+/**
+ * @since 31.0.0
+ */
+class TypeConflictException extends UserPreferencesException {
+}
diff --git a/lib/public/UserPreferences/Exceptions/UnknownKeyException.php b/lib/public/UserPreferences/Exceptions/UnknownKeyException.php
new file mode 100644
index 0000000000000..3df666899641c
--- /dev/null
+++ b/lib/public/UserPreferences/Exceptions/UnknownKeyException.php
@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\UserPreferences\Exceptions;
+
+/**
+ * @since 31.0.0
+ */
+class UnknownKeyException extends UserPreferencesException {
+}
diff --git a/lib/public/UserPreferences/Exceptions/UserPreferencesException.php b/lib/public/UserPreferences/Exceptions/UserPreferencesException.php
new file mode 100644
index 0000000000000..664181d420b7e
--- /dev/null
+++ b/lib/public/UserPreferences/Exceptions/UserPreferencesException.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\UserPreferences\Exceptions;
+
+use Exception;
+
+/**
+ * @since 31.0.0
+ */
+class UserPreferencesException extends Exception {
+}
diff --git a/lib/public/UserPreferences/IUserPreferences.php b/lib/public/UserPreferences/IUserPreferences.php
new file mode 100644
index 0000000000000..757e6405c5b43
--- /dev/null
+++ b/lib/public/UserPreferences/IUserPreferences.php
@@ -0,0 +1,517 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\UserPreferences;
+
+use OCP\UserPreferences\Exceptions\IncorrectTypeException;
+use OCP\UserPreferences\Exceptions\UnknownKeyException;
+
+/**
+ * @since 31.0.0
+ */
+interface IUserPreferences {
+	/**
+	 * Get list of all userIds with preferences stored in database.
+	 * If $appId is specified, will only limit the search to this value
+	 *
+	 * **WARNING:** ignore any cache and get data directly from database.
+	 *
+	 * @param string $appId optional id of app
+	 *
+	 * @return string[] list of userIds
+	 * @since 31.0.0
+	 */
+	public function getUserIds(string $appId = ''): array;
+
+	/**
+	 * Get list of all apps that have at least one preference
+	 * value related to $userId stored in database
+	 *
+	 * **WARNING:** ignore lazy filtering, all user preferences are loaded from database
+	 *
+	 * @param string $userId id of the user
+	 *
+	 * @return string[] list of app ids
+	 * @since 31.0.0
+	 */
+	public function getApps(string $userId): array;
+
+	/**
+	 * Returns all keys stored in database, related to user+app.
+	 * Please note that the values are not returned.
+	 *
+	 * **WARNING:** ignore lazy filtering, all user preferences are loaded from database
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 *
+	 * @return string[] list of stored preference keys
+	 * @since 31.0.0
+	 */
+	public function getKeys(string $userId, string $app): array;
+
+	/**
+	 * Check if a key exists in the list of stored preference values.
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param bool $lazy search within lazy loaded preferences
+	 *
+	 * @return bool TRUE if key exists
+	 * @since 31.0.0
+	 */
+	public function hasKey(string $userId, string $app, string $key, ?bool $lazy = false): bool;
+
+	/**
+	 * best way to see if a value is set as sensitive (not displayed in report)
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param bool|null $lazy search within lazy loaded preferences
+	 *
+	 * @return bool TRUE if value is sensitive
+	 * @throws UnknownKeyException if preference key is not known
+	 * @since 30.0.0
+	 */
+	public function isSensitive(string $userId, string $app, string $key, ?bool $lazy = false): bool;
+
+	/**
+	 * Returns if the preference key stored in database is lazy loaded
+	 *
+	 * **WARNING:** ignore lazy filtering, all preference values are loaded from database
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 *
+	 * @return bool TRUE if preference is lazy loaded
+	 * @throws UnknownKeyException if preference key is not known
+	 * @see IUserPreferences for details about lazy loading
+	 * @since 30.0.0
+	 */
+	public function isLazy(string $userId, string $app, string $key): bool;
+
+	/**
+	 * List all preference values from an app with preference key starting with $key.
+	 * Returns an array with preference key as key, stored value as value.
+	 *
+	 * **WARNING:** ignore lazy filtering, all preference values are loaded from database
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $prefix preference keys prefix to search, can be empty.
+	 * @param bool $filtered filter sensitive preference values
+	 *
+	 * @return array<string, string|int|float|bool|array> [key => value]
+	 * @since 30.0.0
+	 */
+	public function getAllValues(string $userId, string $app, string $prefix = '', bool $filtered = false): array;
+
+	/**
+	 * List all apps storing a specific preference key and its stored value.
+	 * Returns an array with appId as key, stored value as value.
+	 *
+	 * @param string $userId id of the user
+	 * @param string $key preference key
+	 * @param bool $lazy search within lazy loaded preferences
+	 * @param int|null $typedAs enforce type for the returned values {@see self::VALUE_STRING} and others
+	 *
+	 * @return array<string, string|int|float|bool|array> [appId => value]
+	 * @since 31.0.0
+	 */
+	public function searchValuesByApps(string $userId, string $key, bool $lazy = false, ?ValueType $typedAs = null): array;
+
+	/**
+	 * List all users storing a specific preference key and its stored value.
+	 * Returns an array with userId as key, stored value as value.
+	 *
+	 * **Warning**
+	 *
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param int|null $typedAs enforce type for the returned values {@see self::VALUE_STRING} and others
+	 *
+	 * @return array<string, string|int|float|bool|array> [userId => value]
+	 * @since 31.0.0
+	 */
+	public function searchValuesByUsers(string $app, string $key, ?ValueType $typedAs = null, ?array $userIds = null): array;
+
+	/**
+	 * Get user preference assigned to a preference key.
+	 * If preference key is not found in database, default value is returned.
+	 * If preference key is set as lazy loaded, the $lazy argument needs to be set to TRUE.
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param string $default default value
+	 * @param bool $lazy search within lazy loaded preferences
+	 *
+	 * @return string stored preference value or $default if not set in database
+	 * @since 31.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 * @see getValueInt()
+	 * @see getValueFloat()
+	 * @see getValueBool()
+	 * @see getValueArray()
+	 */
+	public function getValueString(string $userId, string $app, string $key, string $default = '', bool $lazy = false): string;
+
+	/**
+	 * Get preference value assigned to a preference key.
+	 * If preference key is not found in database, default value is returned.
+	 * If preference key is set as lazy loaded, the $lazy argument needs to be set to TRUE.
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param int $default default value
+	 * @param bool $lazy search within lazy loaded preferences
+	 *
+	 * @return int stored preference value or $default if not set in database
+	 * @since 31.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 * @see getValueString()
+	 * @see getValueFloat()
+	 * @see getValueBool()
+	 * @see getValueArray()
+	 */
+	public function getValueInt(string $userId, string $app, string $key, int $default = 0, bool $lazy = false): int;
+
+	/**
+	 * Get preference value assigned to a preference key.
+	 * If preference key is not found in database, default value is returned.
+	 * If preference key is set as lazy loaded, the $lazy argument needs to be set to TRUE.
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param float $default default value
+	 * @param bool $lazy search within lazy loaded preferences
+	 *
+	 * @return float stored preference value or $default if not set in database
+	 * @since 30.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 * @see getValueString()
+	 * @see getValueInt()
+	 * @see getValueBool()
+	 * @see getValueArray()
+	 */
+	public function getValueFloat(string $userId, string $app, string $key, float $default = 0, bool $lazy = false): float;
+
+	/**
+	 * Get preference value assigned to a preference key.
+	 * If preference key is not found in database, default value is returned.
+	 * If preference key is set as lazy loaded, the $lazy argument needs to be set to TRUE.
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param bool $default default value
+	 * @param bool $lazy search within lazy loaded preferences
+	 *
+	 * @return bool stored preference value or $default if not set in database
+	 * @since 30.0.0
+	 * @see IUserPrefences for explanation about lazy loading
+	 * @see getValueString()
+	 * @see getValueInt()
+	 * @see getValueFloat()
+	 * @see getValueArray()
+	 */
+	public function getValueBool(string $userId, string $app, string $key, bool $default = false, bool $lazy = false): bool;
+
+	/**
+	 * Get preference value assigned to a preference key.
+	 * If preference key is not found in database, default value is returned.
+	 * If preference key is set as lazy loaded, the $lazy argument needs to be set to TRUE.
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param array $default default value
+	 * @param bool $lazy search within lazy loaded preferences
+	 *
+	 * @return array stored preference value or $default if not set in database
+	 * @since 30.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 * @see getValueString()
+	 * @see getValueInt()
+	 * @see getValueFloat()
+	 * @see getValueBool()
+	 */
+	public function getValueArray(string $userId, string $app, string $key, array $default = [], bool $lazy = false): array;
+
+	/**
+	 * returns the type of preference value
+	 *
+	 * **WARNING:** ignore lazy filtering, all preference values are loaded from database
+	 *              unless lazy is set to false
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param bool|null $lazy
+	 *
+	 * @return ValueType type of the value
+	 * @throws UnknownKeyException if preference key is not known
+	 * @throws IncorrectTypeException if preferences value type is not known
+	 * @since 31.0.0
+	 */
+	public function getValueType(string $userId, string $app, string $key, ?bool $lazy = null): ValueType;
+
+	/**
+	 * Store a preference key and its value in database
+	 *
+	 * If preference key is already known with the exact same preference value, the database is not updated.
+	 * If preference key is not supposed to be read during the boot of the cloud, it is advised to set it as lazy loaded.
+	 *
+	 * If preference value was previously stored as sensitive or lazy loaded, status cannot be altered without using {@see deleteKey()} first
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param string $value preference value
+	 * @param bool $sensitive if TRUE value will be hidden when listing preference values.
+	 * @param bool $lazy set preference as lazy loaded
+	 *
+	 * @return bool TRUE if value was different, therefor updated in database
+	 * @since 30.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 * @see setValueInt()
+	 * @see setValueFloat()
+	 * @see setValueBool()
+	 * @see setValueArray()
+	 */
+	public function setValueString(string $userId, string $app, string $key, string $value, bool $lazy = false, bool $sensitive = false): bool;
+
+	/**
+	 * Store a preference key and its value in database
+	 *
+	 * When handling huge value around and/or above 2,147,483,647, a debug log will be generated
+	 * on 64bits system, as php int type reach its limit (and throw an exception) on 32bits when using huge numbers.
+	 *
+	 * When using huge numbers, it is advised to use {@see \OCP\Util::numericToNumber()} and {@see setValueString()}
+	 *
+	 * If preference key is already known with the exact same preference value, the database is not updated.
+	 * If preference key is not supposed to be read during the boot of the cloud, it is advised to set it as lazy loaded.
+	 *
+	 * If preference value was previously stored as sensitive or lazy loaded, status cannot be altered without using {@see deleteKey()} first
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param int $value preference value
+	 * @param bool $sensitive if TRUE value will be hidden when listing preference values.
+	 * @param bool $lazy set preference as lazy loaded
+	 *
+	 * @return bool TRUE if value was different, therefor updated in database
+	 * @since 30.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 * @see setValueString()
+	 * @see setValueFloat()
+	 * @see setValueBool()
+	 * @see setValueArray()
+	 */
+	public function setValueInt(string $userId, string $app, string $key, int $value, bool $lazy = false, bool $sensitive = false): bool;
+
+	/**
+	 * Store a preference key and its value in database.
+	 *
+	 * If preference key is already known with the exact same preference value, the database is not updated.
+	 * If preference key is not supposed to be read during the boot of the cloud, it is advised to set it as lazy loaded.
+	 *
+	 * If preference value was previously stored as sensitive or lazy loaded, status cannot be altered without using {@see deleteKey()} first
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param float $value preference value
+	 * @param bool $sensitive if TRUE value will be hidden when listing preference values.
+	 * @param bool $lazy set preference as lazy loaded
+	 *
+	 * @return bool TRUE if value was different, therefor updated in database
+	 * @since 30.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 * @see setValueString()
+	 * @see setValueInt()
+	 * @see setValueBool()
+	 * @see setValueArray()
+	 */
+	public function setValueFloat(string $userId, string $app, string $key, float $value, bool $lazy = false, bool $sensitive = false): bool;
+
+	/**
+	 * Store a preference key and its value in database
+	 *
+	 * If preference key is already known with the exact same preference value, the database is not updated.
+	 * If preference key is not supposed to be read during the boot of the cloud, it is advised to set it as lazy loaded.
+	 *
+	 * If preference value was previously stored as lazy loaded, status cannot be altered without using {@see deleteKey()} first
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param bool $value preference value
+	 * @param bool $lazy set preference as lazy loaded
+	 *
+	 * @return bool TRUE if value was different, therefor updated in database
+	 * @since 30.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 * @see setValueString()
+	 * @see setValueInt()
+	 * @see setValueFloat()
+	 * @see setValueArray()
+	 */
+	public function setValueBool(string $userId, string $app, string $key, bool $value, bool $lazy = false): bool;
+
+	/**
+	 * Store a preference key and its value in database
+	 *
+	 * If preference key is already known with the exact same preference value, the database is not updated.
+	 * If preference key is not supposed to be read during the boot of the cloud, it is advised to set it as lazy loaded.
+	 *
+	 * If preference value was previously stored as sensitive or lazy loaded, status cannot be altered without using {@see deleteKey()} first
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param array $value preference value
+	 * @param bool $sensitive if TRUE value will be hidden when listing preference values.
+	 * @param bool $lazy set preference as lazy loaded
+	 *
+	 * @return bool TRUE if value was different, therefor updated in database
+	 * @since 31.0.0
+	 * @see IUserPreferences for explanation about lazy loading
+	 * @see setValueString()
+	 * @see setValueInt()
+	 * @see setValueFloat()
+	 * @see setValueBool()
+	 */
+	public function setValueArray(string $userId, string $app, string $key, array $value, bool $lazy = false, bool $sensitive = false): bool;
+
+	/**
+	 * switch sensitive status of a preference value
+	 *
+	 * **WARNING:** ignore lazy filtering, all preference values are loaded from database
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param bool $sensitive TRUE to set as sensitive, FALSE to unset
+	 *
+	 * @return bool TRUE if database update were necessary
+	 * @since 31.0.0
+	 */
+	public function updateSensitive(string $userId, string $app, string $key, bool $sensitive): bool;
+
+	/**
+	 * switch sensitive loading status of a preference key for all users
+	 *
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param bool $sensitive TRUE to set as sensitive, FALSE to unset
+	 * @since 31.0.0
+	 */
+	public function updateGlobalSensitive(string $app, string $key, bool $sensitive): void;
+
+	/**
+	 * switch lazy loading status of a preference value
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param bool $lazy TRUE to set as lazy loaded, FALSE to unset
+	 *
+	 * @return bool TRUE if database update was necessary
+	 * @since 31.0.0
+	 */
+	public function updateLazy(string $userId, string $app, string $key, bool $lazy): bool;
+
+	/**
+	 * switch lazy loading status of a preference key for all users
+	 *
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 * @param bool $lazy TRUE to set as lazy loaded, FALSE to unset
+	 * @since 31.0.0
+	 */
+	public function updateGlobalLazy(string $app, string $key, bool $lazy): void;
+
+	/**
+	 * returns an array contains details about a preference value
+	 *
+	 * ```
+	 * [
+	 *   "app" => "myapp",
+	 *   "key" => "mykey",
+	 *   "value" => "its_value",
+	 *   "lazy" => false,
+	 *   "type" => 4,
+	 *   "typeString" => "string",
+	 *   'sensitive' => true
+	 * ]
+	 * ```
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 *
+	 * @return array
+	 * @throws UnknownKeyException if preference key is not known in database
+	 * @since 31.0.0
+	 */
+	public function getDetails(string $userId, string $app, string $key): array;
+
+	/**
+	 * Delete single preference key from database.
+	 *
+	 * @param string $userId id of the user
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 *
+	 * @since 31.0.0
+	 */
+	public function deletePreference(string $userId, string $app, string $key): void;
+
+	/**
+	 * @param string $app id of the app
+	 * @param string $key preference key
+	 *
+	 * @since 31.0.0
+	 */
+	public function deleteKey(string $app, string $key): void;
+
+	/**
+	 * delete all preference keys linked to an app
+	 *
+	 * @param string $app id of the app
+	 * @since 31.0.0
+	 */
+	public function deleteApp(string $app): void;
+
+	/**
+	 * Clear the cache for a single user
+	 *
+	 * The cache will be rebuilt only the next time a user preference is requested.
+	 *
+	 * @param string $userId id of the user
+	 * @param bool $reload set to TRUE to refill cache instantly after clearing it
+	 *
+	 * @since 31.0.0
+	 */
+	public function clearCache(string $userId, bool $reload = false): void;
+
+	/**
+	 * Clear the cache for all users.
+	 * The cache will be rebuilt only the next time a user preference is requested.
+	 *
+	 * @since 31.0.0
+	 */
+	public function clearCacheAll(): void;
+}
diff --git a/lib/public/UserPreferences/ValueType.php b/lib/public/UserPreferences/ValueType.php
new file mode 100644
index 0000000000000..57f65b504c7ff
--- /dev/null
+++ b/lib/public/UserPreferences/ValueType.php
@@ -0,0 +1,111 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\UserPreferences;
+
+use OCP\UserPreferences\Exceptions\IncorrectTypeException;
+use UnhandledMatchError;
+use ValueError;
+
+/**
+ * Listing of available value type for user preferences
+ *
+ * @see IUserPreferences
+ * @since 31.0.0
+ */
+enum ValueType: int {
+	/** @since 31.0.0 */
+	case SENSITIVE = 1;
+	/** @since 31.0.0 */
+	case MIXED = 2;
+	/** @since 31.0.0 */
+	case STRING = 4;
+	/** @since 31.0.0 */
+	case INT = 8;
+	/** @since 31.0.0 */
+	case FLOAT = 16;
+	/** @since 31.0.0 */
+	case BOOL = 32;
+	/** @since 31.0.0 */
+	case ARRAY = 64;
+
+	/**
+	 * get ValueType from string based on ValueTypeDefinition
+	 *
+	 * @param string $definition
+	 *
+	 * @return self
+	 * @throws IncorrectTypeException
+	 * @since 31.0.0
+	 */
+	public function fromStringDefinition(string $definition): self {
+		try {
+			return $this->fromValueDefinition(ValueTypeDefinition::from($definition));
+		} catch (ValueError) {
+			throw new IncorrectTypeException('unknown string definition');
+		}
+	}
+
+	/**
+	 * get ValueType from ValueTypeDefinition
+	 *
+	 * @param ValueTypeDefinition $definition
+	 *
+	 * @return self
+	 * @throws IncorrectTypeException
+	 * @since 31.0.0
+	 */
+	public function fromValueDefinition(ValueTypeDefinition $definition): self {
+		try {
+			return match ($definition) {
+				ValueTypeDefinition::MIXED => self::MIXED,
+				ValueTypeDefinition::STRING => self::STRING,
+				ValueTypeDefinition::INT => self::INT,
+				ValueTypeDefinition::FLOAT => self::FLOAT,
+				ValueTypeDefinition::BOOL => self::BOOL,
+				ValueTypeDefinition::ARRAY => self::ARRAY
+			};
+		} catch (UnhandledMatchError) {
+			throw new IncorrectTypeException('unknown definition ' . $definition->value);
+		}
+	}
+
+	/**
+	 * get string definition for current enum value
+	 *
+	 * @return string
+	 * @throws IncorrectTypeException
+	 * @since 31.0.0
+	 */
+	public function getDefinition(): string {
+		return $this->getValueTypeDefinition()->value;
+	}
+
+	/**
+	 * get ValueTypeDefinition for current enum value
+	 *
+	 * @return ValueTypeDefinition
+	 * @throws IncorrectTypeException
+	 * @since 31.0.0
+	 */
+	public function getValueTypeDefinition(): ValueTypeDefinition {
+		try {
+			/** @psalm-suppress UnhandledMatchCondition */
+			return match ($this) {
+				self::MIXED => ValueTypeDefinition::MIXED,
+				self::STRING => ValueTypeDefinition::STRING,
+				self::INT => ValueTypeDefinition::INT,
+				self::FLOAT => ValueTypeDefinition::FLOAT,
+				self::BOOL => ValueTypeDefinition::BOOL,
+				self::ARRAY => ValueTypeDefinition::ARRAY,
+			};
+		} catch (UnhandledMatchError) {
+			throw new IncorrectTypeException('unknown type definition ' . $this->value);
+		}
+	}
+}
diff --git a/lib/public/UserPreferences/ValueTypeDefinition.php b/lib/public/UserPreferences/ValueTypeDefinition.php
new file mode 100644
index 0000000000000..116c20b3bafb0
--- /dev/null
+++ b/lib/public/UserPreferences/ValueTypeDefinition.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCP\UserPreferences;
+
+/**
+ * Listing of value type definition for user preferences
+ *
+ * @see IUserPreferences
+ * @since 31.0.0
+ */
+enum ValueTypeDefinition: string {
+	/** @since 30.0.0 */
+	case MIXED = 'mixed';
+	/** @since 30.0.0 */
+	case STRING = 'string';
+	/** @since 30.0.0 */
+	case INT = 'int';
+	/** @since 30.0.0 */
+	case FLOAT = 'float';
+	/** @since 30.0.0 */
+	case BOOL = 'bool';
+	/** @since 30.0.0 */
+	case ARRAY = 'array';
+}
diff --git a/version.php b/version.php
index e020e4f483a39..24c7289a98dca 100644
--- a/version.php
+++ b/version.php
@@ -9,7 +9,7 @@
 // between betas, final and RCs. This is _not_ the public version number. Reset minor/patch level
 // when updating major/minor version number.
 
-$OC_Version = [31, 0, 0, 2];
+$OC_Version = [31, 0, 0, 3];
 
 // The human-readable string
 $OC_VersionString = '31.0.0 dev';