diff --git a/apps/theming/composer/composer/autoload_classmap.php b/apps/theming/composer/composer/autoload_classmap.php
index 9b53c0f9fea27..931bc2a9c7d9c 100644
--- a/apps/theming/composer/composer/autoload_classmap.php
+++ b/apps/theming/composer/composer/autoload_classmap.php
@@ -10,6 +10,7 @@
     'OCA\\Theming\\AppInfo\\Application' => $baseDir . '/../lib/AppInfo/Application.php',
     'OCA\\Theming\\Capabilities' => $baseDir . '/../lib/Capabilities.php',
     'OCA\\Theming\\Command\\UpdateConfig' => $baseDir . '/../lib/Command/UpdateConfig.php',
+    'OCA\\Theming\\ConfigLexicon' => $baseDir . '/../lib/ConfigLexicon.php',
     'OCA\\Theming\\Controller\\IconController' => $baseDir . '/../lib/Controller/IconController.php',
     'OCA\\Theming\\Controller\\ThemingController' => $baseDir . '/../lib/Controller/ThemingController.php',
     'OCA\\Theming\\Controller\\UserThemeController' => $baseDir . '/../lib/Controller/UserThemeController.php',
diff --git a/apps/theming/composer/composer/autoload_static.php b/apps/theming/composer/composer/autoload_static.php
index 184d9ed07615b..67f80c7aff03a 100644
--- a/apps/theming/composer/composer/autoload_static.php
+++ b/apps/theming/composer/composer/autoload_static.php
@@ -25,6 +25,7 @@ class ComposerStaticInitTheming
         'OCA\\Theming\\AppInfo\\Application' => __DIR__ . '/..' . '/../lib/AppInfo/Application.php',
         'OCA\\Theming\\Capabilities' => __DIR__ . '/..' . '/../lib/Capabilities.php',
         'OCA\\Theming\\Command\\UpdateConfig' => __DIR__ . '/..' . '/../lib/Command/UpdateConfig.php',
+        'OCA\\Theming\\ConfigLexicon' => __DIR__ . '/..' . '/../lib/ConfigLexicon.php',
         'OCA\\Theming\\Controller\\IconController' => __DIR__ . '/..' . '/../lib/Controller/IconController.php',
         'OCA\\Theming\\Controller\\ThemingController' => __DIR__ . '/..' . '/../lib/Controller/ThemingController.php',
         'OCA\\Theming\\Controller\\UserThemeController' => __DIR__ . '/..' . '/../lib/Controller/UserThemeController.php',
diff --git a/apps/theming/lib/ConfigLexicon.php b/apps/theming/lib/ConfigLexicon.php
new file mode 100644
index 0000000000000..37ff0f8359679
--- /dev/null
+++ b/apps/theming/lib/ConfigLexicon.php
@@ -0,0 +1,119 @@
+<?php
+
+declare(strict_types=1);
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OCA\Theming;
+
+use OCP\Config\Lexicon\Entry;
+use OCP\Config\Lexicon\ILexicon;
+use OCP\Config\Lexicon\Strictness;
+use OCP\Config\ValueType;
+
+/**
+ * Config Lexicon for theming.
+ *
+ * Please Add & Manage your Config Keys in that file and keep the Lexicon up to date!
+ *
+ * {@see ILexicon}
+ */
+class ConfigLexicon implements ILexicon {
+	/** The cache buster index */
+	public const CACHE_BUSTER = 'cachebuster';
+	public const USER_THEMING_DISABLED = 'disable-user-theming';
+
+	/** Name of the software running on this instance (usually "Nextcloud") */
+	public const PRODUCT_NAME = 'productName';
+	/** Short name of this instance */
+	public const INSTANCE_NAME = 'name';
+	/** Slogan of this instance */
+	public const INSTANCE_SLOGAN = 'slogan';
+	/** Imprint URL of this instance */
+	public const INSTANCE_IMPRINT_URL = 'imprintUrl';
+	/** Privacy URL of this instance */
+	public const INSTANCE_PRIVACY_URL = 'privacyUrl';
+
+	public const PRIMARY_COLOR = 'primary_color';
+	public const BACKGROUND_COLOR = 'background_color';
+
+	// legacy theming
+	/** Base URL of this instance */
+	public const BASE_URL = 'url';
+	/** Base URL for documentation */
+	public const DOC_BASE_URL = 'docBaseUrl';
+
+	public function getStrictness(): Strictness {
+		return Strictness::NOTICE;
+	}
+
+	public function getAppConfigs(): array {
+		return [
+			// internals
+			new Entry(
+				self::CACHE_BUSTER,
+				ValueType::INT,
+				defaultRaw: 0,
+				definition: 'The current cache buster key for theming assets.',
+			),
+			new Entry(
+				self::USER_THEMING_DISABLED,
+				ValueType::BOOL,
+				defaultRaw: false,
+				definition: 'Whether user theming is disabled.',
+			),
+
+			// instance theming
+			new Entry(
+				self::PRODUCT_NAME,
+				ValueType::STRING,
+				defaultRaw: 'Nextcloud',
+				definition: 'The name of the software running on this instance (usually "Nextcloud").',
+			),
+			new Entry(
+				self::INSTANCE_NAME,
+				ValueType::STRING,
+				defaultRaw: '',
+				definition: 'Short name of this instance.',
+			),
+			new Entry(
+				self::INSTANCE_SLOGAN,
+				ValueType::STRING,
+				defaultRaw: '',
+				definition: 'Slogan of this instance.',
+			),
+			new Entry(
+				self::INSTANCE_IMPRINT_URL,
+				ValueType::STRING,
+				defaultRaw: '',
+				definition: 'Imprint URL of this instance.',
+			),
+			new Entry(
+				self::INSTANCE_PRIVACY_URL,
+				ValueType::STRING,
+				defaultRaw: '',
+				definition: 'Privacy URL of this instance.',
+			),
+
+			// legacy theming
+			new Entry(
+				self::BASE_URL,
+				ValueType::STRING,
+				defaultRaw: '',
+				definition: 'Base URL of this instance.',
+			),
+			new Entry(
+				self::DOC_BASE_URL,
+				ValueType::STRING,
+				defaultRaw: '',
+				definition: 'Base URL for documentation.',
+			),
+		];
+	}
+
+	public function getUserConfigs(): array {
+		return [];
+	}
+}
diff --git a/apps/theming/lib/ThemingDefaults.php b/apps/theming/lib/ThemingDefaults.php
index 71afae14a8ea7..f90e943c1f25e 100644
--- a/apps/theming/lib/ThemingDefaults.php
+++ b/apps/theming/lib/ThemingDefaults.php
@@ -10,9 +10,9 @@
 use OCA\Theming\Service\BackgroundService;
 use OCP\App\AppPathNotFoundException;
 use OCP\App\IAppManager;
+use OCP\AppFramework\Services\IAppConfig;
 use OCP\Files\NotFoundException;
 use OCP\Files\SimpleFS\ISimpleFile;
-use OCP\IAppConfig;
 use OCP\ICacheFactory;
 use OCP\IConfig;
 use OCP\IL10N;
@@ -69,27 +69,27 @@ public function __construct(
 	}
 
 	public function getName() {
-		return strip_tags($this->config->getAppValue('theming', 'name', $this->name));
+		return strip_tags($this->appConfig->getAppValueString(ConfigLexicon::INSTANCE_NAME, $this->name));
 	}
 
 	public function getHTMLName() {
-		return $this->config->getAppValue('theming', 'name', $this->name);
+		return $this->appConfig->getAppValueString(ConfigLexicon::INSTANCE_NAME, $this->name);
 	}
 
 	public function getTitle() {
-		return strip_tags($this->config->getAppValue('theming', 'name', $this->title));
+		return strip_tags($this->appConfig->getAppValueString(ConfigLexicon::INSTANCE_NAME, $this->title));
 	}
 
 	public function getEntity() {
-		return strip_tags($this->config->getAppValue('theming', 'name', $this->entity));
+		return strip_tags($this->appConfig->getAppValueString(ConfigLexicon::INSTANCE_NAME, $this->entity));
 	}
 
 	public function getProductName() {
-		return strip_tags($this->config->getAppValue('theming', 'productName', $this->productName));
+		return strip_tags($this->appConfig->getAppValueString(ConfigLexicon::PRODUCT_NAME, $this->productName));
 	}
 
 	public function getBaseUrl() {
-		return $this->config->getAppValue('theming', 'url', $this->url);
+		return $this->appConfig->getAppValueString(ConfigLexicon::BASE_URL, $this->url);
 	}
 
 	/**
@@ -97,20 +97,20 @@ public function getBaseUrl() {
 	 * @psalm-suppress InvalidReturnStatement
 	 * @psalm-suppress InvalidReturnType
 	 */
-	public function getSlogan(?string $lang = null) {
-		return \OCP\Util::sanitizeHTML($this->config->getAppValue('theming', 'slogan', parent::getSlogan($lang)));
+	public function getSlogan(?string $lang = null): string {
+		return \OCP\Util::sanitizeHTML($this->appConfig->getAppValueString(ConfigLexicon::INSTANCE_SLOGAN, parent::getSlogan($lang)));
 	}
 
-	public function getImprintUrl() {
-		return (string)$this->config->getAppValue('theming', 'imprintUrl', '');
+	public function getImprintUrl(): string {
+		return $this->appConfig->getAppValueString(ConfigLexicon::INSTANCE_IMPRINT_URL, '');
 	}
 
-	public function getPrivacyUrl() {
-		return (string)$this->config->getAppValue('theming', 'privacyUrl', '');
+	public function getPrivacyUrl(): string {
+		return $this->appConfig->getAppValueString(ConfigLexicon::INSTANCE_PRIVACY_URL, '');
 	}
 
-	public function getDocBaseUrl() {
-		return (string)$this->config->getAppValue('theming', 'docBaseUrl', $this->docBaseUrl);
+	public function getDocBaseUrl(): string {
+		return $this->appConfig->getAppValueString(ConfigLexicon::DOC_BASE_URL, $this->docBaseUrl);
 	}
 
 	public function getShortFooter() {
@@ -121,7 +121,7 @@ public function getShortFooter() {
 
 		if ($entity !== '') {
 			if ($baseUrl !== '') {
-				$footer = '<a href="' . $baseUrl . '" target="_blank"'
+				$footer = '<a href="' . htmlspecialchars($baseUrl) . '" target="_blank"'
 					. ' rel="noreferrer noopener" class="entity-name">' . $entity . '</a>';
 			} else {
 				$footer = '<span class="entity-name">' . $entity . '</span>';
@@ -132,11 +132,11 @@ public function getShortFooter() {
 		$links = [
 			[
 				'text' => $this->l->t('Legal notice'),
-				'url' => (string)$this->getImprintUrl()
+				'url' => $this->getImprintUrl()
 			],
 			[
 				'text' => $this->l->t('Privacy policy'),
-				'url' => (string)$this->getPrivacyUrl()
+				'url' => $this->getPrivacyUrl()
 			],
 		];
 
@@ -155,7 +155,7 @@ public function getShortFooter() {
 			if ($link['url'] !== ''
 				&& filter_var($link['url'], FILTER_VALIDATE_URL)
 			) {
-				$legalLinks .= $divider . '<a href="' . $link['url'] . '" class="legal" target="_blank"'
+				$legalLinks .= $divider . '<a href="' . htmlspecialchars($link['url']) . '" class="legal" target="_blank"'
 					. ' rel="noreferrer noopener">' . $link['text'] . '</a>';
 				$divider = ' · ';
 			}
@@ -224,7 +224,7 @@ public function getColorBackground(): string {
 	 */
 	public function getDefaultColorPrimary(): string {
 		// try admin color
-		$defaultColor = $this->appConfig->getValueString(Application::APP_ID, 'primary_color', '');
+		$defaultColor = $this->appConfig->getAppValueString('primary_color', '');
 		if (preg_match('/^\#([0-9a-f]{3}|[0-9a-f]{6})$/i', $defaultColor)) {
 			return $defaultColor;
 		}
@@ -237,7 +237,7 @@ public function getDefaultColorPrimary(): string {
 	 * Default background color only taking admin setting into account
 	 */
 	public function getDefaultColorBackground(): string {
-		$defaultColor = $this->appConfig->getValueString(Application::APP_ID, 'background_color');
+		$defaultColor = $this->appConfig->getAppValueString('background_color', '');
 		if (preg_match('/^\#([0-9a-f]{3}|[0-9a-f]{6})$/i', $defaultColor)) {
 			return $defaultColor;
 		}
@@ -252,14 +252,14 @@ public function getDefaultColorBackground(): string {
 	 * @return string
 	 */
 	public function getLogo($useSvg = true): string {
-		$logo = $this->config->getAppValue('theming', 'logoMime', '');
+		$logo = $this->appConfig->getAppValueString('logoMime', '');
 
 		// short cut to avoid setting up the filesystem just to check if the logo is there
 		//
 		// explanation: if an SVG is requested and the app config value for logoMime is set then the logo is there.
 		// otherwise we need to check it and maybe also generate a PNG from the SVG (that's done in getImage() which
 		// needs to be called then)
-		if ($useSvg === true && $logo !== false) {
+		if ($useSvg === true && $logo !== '') {
 			$logoExists = true;
 		} else {
 			try {
@@ -270,8 +270,7 @@ public function getLogo($useSvg = true): string {
 			}
 		}
 
-		$cacheBusterCounter = $this->config->getAppValue('theming', 'cachebuster', '0');
-
+		$cacheBusterCounter = (string)$this->appConfig->getAppValueInt(ConfigLexicon::CACHE_BUSTER);
 		if (!$logo || !$logoExists) {
 			if ($useSvg) {
 				$logo = $this->urlGenerator->imagePath('core', 'logo/logo.svg');
@@ -298,28 +297,28 @@ public function getBackground(bool $darkVariant = false): string {
 	 * @return string
 	 */
 	public function getiTunesAppId() {
-		return $this->config->getAppValue('theming', 'iTunesAppId', $this->iTunesAppId);
+		return $this->appConfig->getAppValueString('iTunesAppId', $this->iTunesAppId);
 	}
 
 	/**
 	 * @return string
 	 */
 	public function getiOSClientUrl() {
-		return $this->config->getAppValue('theming', 'iOSClientUrl', $this->iOSClientUrl);
+		return $this->appConfig->getAppValueString('iOSClientUrl', $this->iOSClientUrl);
 	}
 
 	/**
 	 * @return string
 	 */
 	public function getAndroidClientUrl() {
-		return $this->config->getAppValue('theming', 'AndroidClientUrl', $this->AndroidClientUrl);
+		return $this->appConfig->getAppValueString('AndroidClientUrl', $this->AndroidClientUrl);
 	}
 
 	/**
 	 * @return string
 	 */
 	public function getFDroidClientUrl() {
-		return $this->config->getAppValue('theming', 'FDroidClientUrl', $this->FDroidClientUrl);
+		return $this->appConfig->getAppValueString('FDroidClientUrl', $this->FDroidClientUrl);
 	}
 
 	/**
@@ -327,7 +326,7 @@ public function getFDroidClientUrl() {
 	 * @deprecated since Nextcloud 22 - https://github.com/nextcloud/server/issues/9940
 	 */
 	public function getScssVariables() {
-		$cacheBuster = $this->config->getAppValue('theming', 'cachebuster', '0');
+		$cacheBuster = $this->appConfig->getAppValueInt(ConfigLexicon::CACHE_BUSTER);
 		$cache = $this->cacheFactory->createDistributed('theming-' . $cacheBuster . '-' . $this->urlGenerator->getBaseUrl());
 		if ($value = $cache->get('getScssVariables')) {
 			return $value;
@@ -335,10 +334,10 @@ public function getScssVariables() {
 
 		$variables = [
 			'theming-cachebuster' => "'" . $cacheBuster . "'",
-			'theming-logo-mime' => "'" . $this->config->getAppValue('theming', 'logoMime') . "'",
-			'theming-background-mime' => "'" . $this->config->getAppValue('theming', 'backgroundMime') . "'",
-			'theming-logoheader-mime' => "'" . $this->config->getAppValue('theming', 'logoheaderMime') . "'",
-			'theming-favicon-mime' => "'" . $this->config->getAppValue('theming', 'faviconMime') . "'"
+			'theming-logo-mime' => "'" . $this->appConfig->getAppValueString('logoMime') . "'",
+			'theming-background-mime' => "'" . $this->appConfig->getAppValueString('backgroundMime') . "'",
+			'theming-logoheader-mime' => "'" . $this->appConfig->getAppValueString('logoheaderMime') . "'",
+			'theming-favicon-mime' => "'" . $this->appConfig->getAppValueString('faviconMime') . "'"
 		];
 
 		$variables['image-logo'] = "url('" . $this->imageManager->getImageUrl('logo') . "')";
@@ -347,13 +346,13 @@ public function getScssVariables() {
 		$variables['image-login-background'] = "url('" . $this->imageManager->getImageUrl('background') . "')";
 		$variables['image-login-plain'] = 'false';
 
-		if ($this->appConfig->getValueString(Application::APP_ID, 'primary_color', '') !== '') {
+		if ($this->appConfig->getAppValueString('primary_color', '') !== '') {
 			$variables['color-primary'] = $this->getColorPrimary();
 			$variables['color-primary-text'] = $this->getTextColorPrimary();
 			$variables['color-primary-element'] = $this->util->elementColor($this->getColorPrimary());
 		}
 
-		if ($this->config->getAppValue('theming', 'backgroundMime', '') === 'backgroundColor') {
+		if ($this->appConfig->getAppValueString('backgroundMime', '') === 'backgroundColor') {
 			$variables['image-login-plain'] = 'true';
 		}
 
@@ -378,7 +377,6 @@ public function replaceImagePath($app, $image) {
 		if ($app === '' || $app === 'files_sharing') {
 			$app = 'core';
 		}
-		$cacheBusterValue = $this->config->getAppValue('theming', 'cachebuster', '0');
 
 		$route = false;
 		if ($image === 'favicon.ico' && ($this->imageManager->shouldReplaceIcons() || $this->getCustomFavicon() !== null)) {
@@ -420,8 +418,8 @@ protected function getCustomFavicon(): ?ISimpleFile {
 	 * Increases the cache buster key
 	 */
 	public function increaseCacheBuster(): void {
-		$cacheBusterKey = (int)$this->config->getAppValue('theming', 'cachebuster', '0');
-		$this->config->setAppValue('theming', 'cachebuster', (string)($cacheBusterKey + 1));
+		$cacheBusterKey = $this->appConfig->getAppValueInt(ConfigLexicon::CACHE_BUSTER);
+		$this->appConfig->setAppValueInt(ConfigLexicon::CACHE_BUSTER, ++$cacheBusterKey);
 		$this->cacheFactory->createDistributed('theming-')->clear();
 		$this->cacheFactory->createDistributed('imagePath')->clear();
 	}
@@ -433,7 +431,18 @@ public function increaseCacheBuster(): void {
 	 * @param string $value
 	 */
 	public function set($setting, $value): void {
-		$this->appConfig->setValueString('theming', $setting, $value);
+		switch ($setting) {
+			case ConfigLexicon::CACHE_BUSTER:
+				$this->appConfig->setAppValueInt(ConfigLexicon::CACHE_BUSTER, (int)$value);
+				break;
+			case ConfigLexicon::USER_THEMING_DISABLED:
+				$value = $value === 'true' || $value === 'yes' || $value === '1';
+				$this->appConfig->setAppValueBool(ConfigLexicon::USER_THEMING_DISABLED, $value);
+				break;
+			default:
+				$this->appConfig->setAppValueString($setting, $value);
+				break;
+		}
 		$this->increaseCacheBuster();
 	}
 
@@ -443,10 +452,10 @@ public function set($setting, $value): void {
 	public function undoAll(): void {
 		// Remember the current cachebuster value, as we do not want to reset this value
 		// Otherwise this can lead to caching issues as the value might be known to a browser already
-		$cacheBusterKey = $this->config->getAppValue('theming', 'cachebuster', '0');
-		$this->config->deleteAppValues('theming');
-		$this->config->setAppValue('theming', 'cachebuster', $cacheBusterKey);
+		$cacheBusterKey = $this->appConfig->getAppValueInt(ConfigLexicon::CACHE_BUSTER);
+		$this->appConfig->deleteAppValues();
 		$this->increaseCacheBuster();
+		$this->appConfig->setAppValueInt(ConfigLexicon::CACHE_BUSTER, $cacheBusterKey);
 	}
 
 	/**
@@ -456,7 +465,7 @@ public function undoAll(): void {
 	 * @return string default value
 	 */
 	public function undo($setting): string {
-		$this->config->deleteAppValue('theming', $setting);
+		$this->appConfig->deleteAppValue($setting);
 		$this->increaseCacheBuster();
 
 		$returnValue = '';
@@ -485,7 +494,7 @@ public function undo($setting): string {
 			case 'background':
 			case 'favicon':
 				$this->imageManager->delete($setting);
-				$this->config->deleteAppValue('theming', $setting . 'Mime');
+				$this->appConfig->deleteAppValue($setting . 'Mime');
 				break;
 		}
 
@@ -523,6 +532,6 @@ public function getDefaultTextColorPrimary() {
 	 * Has the admin disabled user customization
 	 */
 	public function isUserThemingDisabled(): bool {
-		return $this->appConfig->getValueBool(Application::APP_ID, 'disable-user-theming');
+		return $this->appConfig->getAppValueBool(ConfigLexicon::USER_THEMING_DISABLED, false);
 	}
 }
diff --git a/apps/theming/tests/ThemingDefaultsTest.php b/apps/theming/tests/ThemingDefaultsTest.php
index 917ab960318a0..5682798f3f180 100644
--- a/apps/theming/tests/ThemingDefaultsTest.php
+++ b/apps/theming/tests/ThemingDefaultsTest.php
@@ -12,8 +12,8 @@
 use OCA\Theming\ThemingDefaults;
 use OCA\Theming\Util;
 use OCP\App\IAppManager;
+use OCP\AppFramework\Services\IAppConfig;
 use OCP\Files\NotFoundException;
-use OCP\IAppConfig;
 use OCP\ICache;
 use OCP\ICacheFactory;
 use OCP\IConfig;
@@ -28,8 +28,7 @@
 class ThemingDefaultsTest extends TestCase {
 	private IAppConfig&MockObject $appConfig;
 	private IConfig&MockObject $config;
-	private \OC_Defaults $defaults;
-	private IL10N|MockObject $l10n;
+	private IL10N&MockObject $l10n;
 	private IUserSession&MockObject $userSession;
 	private IURLGenerator&MockObject $urlGenerator;
 	private ICacheFactory&MockObject $cacheFactory;
@@ -39,6 +38,8 @@ class ThemingDefaultsTest extends TestCase {
 	private ImageManager&MockObject $imageManager;
 	private INavigationManager&MockObject $navigationManager;
 	private BackgroundService&MockObject $backgroundService;
+
+	private \OC_Defaults $defaults;
 	private ThemingDefaults $template;
 
 	protected function setUp(): void {
@@ -76,60 +77,60 @@ protected function setUp(): void {
 	}
 
 	public function testGetNameWithDefault(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'name', 'Nextcloud')
+			->method('getAppValueString')
+			->with('name', 'Nextcloud')
 			->willReturn('Nextcloud');
 
 		$this->assertEquals('Nextcloud', $this->template->getName());
 	}
 
 	public function testGetNameWithCustom(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'name', 'Nextcloud')
+			->method('getAppValueString')
+			->with('name', 'Nextcloud')
 			->willReturn('MyCustomCloud');
 
 		$this->assertEquals('MyCustomCloud', $this->template->getName());
 	}
 
 	public function testGetHTMLNameWithDefault(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'name', 'Nextcloud')
+			->method('getAppValueString')
+			->with('name', 'Nextcloud')
 			->willReturn('Nextcloud');
 
 		$this->assertEquals('Nextcloud', $this->template->getHTMLName());
 	}
 
 	public function testGetHTMLNameWithCustom(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'name', 'Nextcloud')
+			->method('getAppValueString')
+			->with('name', 'Nextcloud')
 			->willReturn('MyCustomCloud');
 
 		$this->assertEquals('MyCustomCloud', $this->template->getHTMLName());
 	}
 
 	public function testGetTitleWithDefault(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'name', 'Nextcloud')
+			->method('getAppValueString')
+			->with('name', 'Nextcloud')
 			->willReturn('Nextcloud');
 
 		$this->assertEquals('Nextcloud', $this->template->getTitle());
 	}
 
 	public function testGetTitleWithCustom(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'name', 'Nextcloud')
+			->method('getAppValueString')
+			->with('name', 'Nextcloud')
 			->willReturn('MyCustomCloud');
 
 		$this->assertEquals('MyCustomCloud', $this->template->getTitle());
@@ -137,40 +138,40 @@ public function testGetTitleWithCustom(): void {
 
 
 	public function testGetEntityWithDefault(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'name', 'Nextcloud')
+			->method('getAppValueString')
+			->with('name', 'Nextcloud')
 			->willReturn('Nextcloud');
 
 		$this->assertEquals('Nextcloud', $this->template->getEntity());
 	}
 
 	public function testGetEntityWithCustom(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'name', 'Nextcloud')
+			->method('getAppValueString')
+			->with('name', 'Nextcloud')
 			->willReturn('MyCustomCloud');
 
 		$this->assertEquals('MyCustomCloud', $this->template->getEntity());
 	}
 
 	public function testGetBaseUrlWithDefault(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'url', $this->defaults->getBaseUrl())
+			->method('getAppValueString')
+			->with('url', $this->defaults->getBaseUrl())
 			->willReturn($this->defaults->getBaseUrl());
 
 		$this->assertEquals($this->defaults->getBaseUrl(), $this->template->getBaseUrl());
 	}
 
 	public function testGetBaseUrlWithCustom(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'url', $this->defaults->getBaseUrl())
+			->method('getAppValueString')
+			->with('url', $this->defaults->getBaseUrl())
 			->willReturn('https://example.com/');
 
 		$this->assertEquals('https://example.com/', $this->template->getBaseUrl());
@@ -185,10 +186,10 @@ public static function legalUrlProvider(): array {
 
 	#[\PHPUnit\Framework\Attributes\DataProvider('legalUrlProvider')]
 	public function testGetImprintURL(string $imprintUrl): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'imprintUrl', '')
+			->method('getAppValueString')
+			->with('imprintUrl', '')
 			->willReturn($imprintUrl);
 
 		$this->assertEquals($imprintUrl, $this->template->getImprintUrl());
@@ -196,45 +197,45 @@ public function testGetImprintURL(string $imprintUrl): void {
 
 	#[\PHPUnit\Framework\Attributes\DataProvider('legalUrlProvider')]
 	public function testGetPrivacyURL(string $privacyUrl): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'privacyUrl', '')
+			->method('getAppValueString')
+			->with('privacyUrl', '')
 			->willReturn($privacyUrl);
 
 		$this->assertEquals($privacyUrl, $this->template->getPrivacyUrl());
 	}
 
 	public function testGetSloganWithDefault(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'slogan', $this->defaults->getSlogan())
+			->method('getAppValueString')
+			->with('slogan', $this->defaults->getSlogan())
 			->willReturn($this->defaults->getSlogan());
 
 		$this->assertEquals($this->defaults->getSlogan(), $this->template->getSlogan());
 	}
 
 	public function testGetSloganWithCustom(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'slogan', $this->defaults->getSlogan())
+			->method('getAppValueString')
+			->with('slogan', $this->defaults->getSlogan())
 			->willReturn('My custom Slogan');
 
 		$this->assertEquals('My custom Slogan', $this->template->getSlogan());
 	}
 
 	public function testGetShortFooter(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->exactly(5))
-			->method('getAppValue')
+			->method('getAppValueString')
 			->willReturnMap([
-				['theming', 'url', $this->defaults->getBaseUrl(), 'url'],
-				['theming', 'name', 'Nextcloud', 'Name'],
-				['theming', 'slogan', $this->defaults->getSlogan(), 'Slogan'],
-				['theming', 'imprintUrl', '', ''],
-				['theming', 'privacyUrl', '', ''],
+				['url', $this->defaults->getBaseUrl(), 'url'],
+				['name', 'Nextcloud', 'Name'],
+				['slogan', $this->defaults->getSlogan(), 'Slogan'],
+				['imprintUrl', '', ''],
+				['privacyUrl', '', ''],
 			]);
 
 		$this->assertEquals('<a href="url" target="_blank" rel="noreferrer noopener" class="entity-name">Name</a> – Slogan', $this->template->getShortFooter());
@@ -242,15 +243,15 @@ public function testGetShortFooter(): void {
 
 	public function testGetShortFooterEmptyUrl(): void {
 		$this->navigationManager->expects($this->once())->method('getAll')->with(INavigationManager::TYPE_GUEST)->willReturn([]);
-		$this->config
+		$this->appConfig
 			->expects($this->exactly(5))
-			->method('getAppValue')
+			->method('getAppValueString')
 			->willReturnMap([
-				['theming', 'url', $this->defaults->getBaseUrl(), ''],
-				['theming', 'name', 'Nextcloud', 'Name'],
-				['theming', 'slogan', $this->defaults->getSlogan(), 'Slogan'],
-				['theming', 'imprintUrl', '', ''],
-				['theming', 'privacyUrl', '', ''],
+				['url', $this->defaults->getBaseUrl(), ''],
+				['name', 'Nextcloud', 'Name'],
+				['slogan', $this->defaults->getSlogan(), 'Slogan'],
+				['imprintUrl', '', ''],
+				['privacyUrl', '', ''],
 			]);
 
 		$this->assertEquals('<span class="entity-name">Name</span> – Slogan', $this->template->getShortFooter());
@@ -258,15 +259,15 @@ public function testGetShortFooterEmptyUrl(): void {
 
 	public function testGetShortFooterEmptySlogan(): void {
 		$this->navigationManager->expects($this->once())->method('getAll')->with(INavigationManager::TYPE_GUEST)->willReturn([]);
-		$this->config
+		$this->appConfig
 			->expects($this->exactly(5))
-			->method('getAppValue')
+			->method('getAppValueString')
 			->willReturnMap([
-				['theming', 'url', $this->defaults->getBaseUrl(), 'url'],
-				['theming', 'name', 'Nextcloud', 'Name'],
-				['theming', 'slogan', $this->defaults->getSlogan(), ''],
-				['theming', 'imprintUrl', '', ''],
-				['theming', 'privacyUrl', '', ''],
+				['url', $this->defaults->getBaseUrl(), 'url'],
+				['name', 'Nextcloud', 'Name'],
+				['slogan', $this->defaults->getSlogan(), ''],
+				['imprintUrl', '', ''],
+				['privacyUrl', '', ''],
 			]);
 
 		$this->assertEquals('<a href="url" target="_blank" rel="noreferrer noopener" class="entity-name">Name</a>', $this->template->getShortFooter());
@@ -274,15 +275,15 @@ public function testGetShortFooterEmptySlogan(): void {
 
 	public function testGetShortFooterImprint(): void {
 		$this->navigationManager->expects($this->once())->method('getAll')->with(INavigationManager::TYPE_GUEST)->willReturn([]);
-		$this->config
+		$this->appConfig
 			->expects($this->exactly(5))
-			->method('getAppValue')
+			->method('getAppValueString')
 			->willReturnMap([
-				['theming', 'url', $this->defaults->getBaseUrl(), 'url'],
-				['theming', 'name', 'Nextcloud', 'Name'],
-				['theming', 'slogan', $this->defaults->getSlogan(), 'Slogan'],
-				['theming', 'imprintUrl', '', 'https://example.com/imprint'],
-				['theming', 'privacyUrl', '', ''],
+				['url', $this->defaults->getBaseUrl(), 'url'],
+				['name', 'Nextcloud', 'Name'],
+				['slogan', $this->defaults->getSlogan(), 'Slogan'],
+				['imprintUrl', '', 'https://example.com/imprint'],
+				['privacyUrl', '', ''],
 			]);
 
 		$this->l10n
@@ -295,15 +296,15 @@ public function testGetShortFooterImprint(): void {
 
 	public function testGetShortFooterPrivacy(): void {
 		$this->navigationManager->expects($this->once())->method('getAll')->with(INavigationManager::TYPE_GUEST)->willReturn([]);
-		$this->config
+		$this->appConfig
 			->expects($this->exactly(5))
-			->method('getAppValue')
+			->method('getAppValueString')
 			->willReturnMap([
-				['theming', 'url', $this->defaults->getBaseUrl(), 'url'],
-				['theming', 'name', 'Nextcloud', 'Name'],
-				['theming', 'slogan', $this->defaults->getSlogan(), 'Slogan'],
-				['theming', 'imprintUrl', '', ''],
-				['theming', 'privacyUrl', '', 'https://example.com/privacy'],
+				['url', $this->defaults->getBaseUrl(), 'url'],
+				['name', 'Nextcloud', 'Name'],
+				['slogan', $this->defaults->getSlogan(), 'Slogan'],
+				['imprintUrl', '', ''],
+				['privacyUrl', '', 'https://example.com/privacy'],
 			]);
 
 		$this->l10n
@@ -316,15 +317,15 @@ public function testGetShortFooterPrivacy(): void {
 
 	public function testGetShortFooterAllLegalLinks(): void {
 		$this->navigationManager->expects($this->once())->method('getAll')->with(INavigationManager::TYPE_GUEST)->willReturn([]);
-		$this->config
+		$this->appConfig
 			->expects($this->exactly(5))
-			->method('getAppValue')
+			->method('getAppValueString')
 			->willReturnMap([
-				['theming', 'url', $this->defaults->getBaseUrl(), 'url'],
-				['theming', 'name', 'Nextcloud', 'Name'],
-				['theming', 'slogan', $this->defaults->getSlogan(), 'Slogan'],
-				['theming', 'imprintUrl', '', 'https://example.com/imprint'],
-				['theming', 'privacyUrl', '', 'https://example.com/privacy'],
+				['url', $this->defaults->getBaseUrl(), 'url'],
+				['name', 'Nextcloud', 'Name'],
+				['slogan', $this->defaults->getSlogan(), 'Slogan'],
+				['imprintUrl', '', 'https://example.com/imprint'],
+				['privacyUrl', '', 'https://example.com/privacy'],
 			]);
 
 		$this->l10n
@@ -345,15 +346,15 @@ public static function invalidLegalUrlProvider(): array {
 	#[\PHPUnit\Framework\Attributes\DataProvider('invalidLegalUrlProvider')]
 	public function testGetShortFooterInvalidImprint(string $invalidImprintUrl): void {
 		$this->navigationManager->expects($this->once())->method('getAll')->with(INavigationManager::TYPE_GUEST)->willReturn([]);
-		$this->config
+		$this->appConfig
 			->expects($this->exactly(5))
-			->method('getAppValue')
+			->method('getAppValueString')
 			->willReturnMap([
-				['theming', 'url', $this->defaults->getBaseUrl(), 'url'],
-				['theming', 'name', 'Nextcloud', 'Name'],
-				['theming', 'slogan', $this->defaults->getSlogan(), 'Slogan'],
-				['theming', 'imprintUrl', '', $invalidImprintUrl],
-				['theming', 'privacyUrl', '', ''],
+				['url', $this->defaults->getBaseUrl(), 'url'],
+				['name', 'Nextcloud', 'Name'],
+				['slogan', $this->defaults->getSlogan(), 'Slogan'],
+				['imprintUrl', '', $invalidImprintUrl],
+				['privacyUrl', '', ''],
 			]);
 
 		$this->assertEquals('<a href="url" target="_blank" rel="noreferrer noopener" class="entity-name">Name</a> – Slogan', $this->template->getShortFooter());
@@ -362,15 +363,15 @@ public function testGetShortFooterInvalidImprint(string $invalidImprintUrl): voi
 	#[\PHPUnit\Framework\Attributes\DataProvider('invalidLegalUrlProvider')]
 	public function testGetShortFooterInvalidPrivacy(string $invalidPrivacyUrl): void {
 		$this->navigationManager->expects($this->once())->method('getAll')->with(INavigationManager::TYPE_GUEST)->willReturn([]);
-		$this->config
+		$this->appConfig
 			->expects($this->exactly(5))
-			->method('getAppValue')
+			->method('getAppValueString')
 			->willReturnMap([
-				['theming', 'url', $this->defaults->getBaseUrl(), 'url'],
-				['theming', 'name', 'Nextcloud', 'Name'],
-				['theming', 'slogan', $this->defaults->getSlogan(), 'Slogan'],
-				['theming', 'imprintUrl', '', ''],
-				['theming', 'privacyUrl', '', $invalidPrivacyUrl],
+				['url', $this->defaults->getBaseUrl(), 'url'],
+				['name', 'Nextcloud', 'Name'],
+				['slogan', $this->defaults->getSlogan(), 'Slogan'],
+				['imprintUrl', '', ''],
+				['privacyUrl', '', $invalidPrivacyUrl],
 			]);
 
 		$this->assertEquals('<a href="url" target="_blank" rel="noreferrer noopener" class="entity-name">Name</a> – Slogan', $this->template->getShortFooter());
@@ -379,13 +380,13 @@ public function testGetShortFooterInvalidPrivacy(string $invalidPrivacyUrl): voi
 	public function testGetColorPrimaryWithDefault(): void {
 		$this->appConfig
 			->expects(self::once())
-			->method('getValueBool')
-			->with('theming', 'disable-user-theming')
+			->method('getAppValueBool')
+			->with('disable-user-theming')
 			->willReturn(false);
 		$this->appConfig
 			->expects(self::once())
-			->method('getValueString')
-			->with('theming', 'primary_color', '')
+			->method('getAppValueString')
+			->with('primary_color', '')
 			->willReturn($this->defaults->getColorPrimary());
 
 		$this->assertEquals($this->defaults->getColorPrimary(), $this->template->getColorPrimary());
@@ -394,13 +395,13 @@ public function testGetColorPrimaryWithDefault(): void {
 	public function testGetColorPrimaryWithCustom(): void {
 		$this->appConfig
 			->expects(self::once())
-			->method('getValueBool')
-			->with('theming', 'disable-user-theming')
+			->method('getAppValueBool')
+			->with('disable-user-theming')
 			->willReturn(false);
 		$this->appConfig
 			->expects(self::once())
-			->method('getValueString')
-			->with('theming', 'primary_color', '')
+			->method('getAppValueString')
+			->with('primary_color', '')
 			->willReturn('#fff');
 
 		$this->assertEquals('#fff', $this->template->getColorPrimary());
@@ -458,13 +459,13 @@ public function testGetColorPrimary(bool $disableTheming, string $primaryColor,
 			->willReturn('user');
 		$this->appConfig
 			->expects(self::any())
-			->method('getValueBool')
-			->with('theming', 'disable-user-theming')
+			->method('getAppValueBool')
+			->with('disable-user-theming')
 			->willReturn($disableTheming);
 		$this->appConfig
 			->expects(self::any())
-			->method('getValueString')
-			->with('theming', 'primary_color', '')
+			->method('getAppValueString')
+			->with('primary_color', '')
 			->willReturn($primaryColor);
 		$this->config
 			->expects($this->any())
@@ -476,19 +477,19 @@ public function testGetColorPrimary(bool $disableTheming, string $primaryColor,
 	}
 
 	public function testSet(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('setAppValue')
-			->with('theming', 'cachebuster', 16);
+			->method('setAppValueInt')
+			->with('cachebuster', 16);
 		$this->appConfig
 			->expects($this->once())
-			->method('setValueString')
-			->with('theming', 'MySetting', 'MyValue');
-		$this->config
+			->method('setAppValueString')
+			->with('MySetting', 'MyValue');
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'cachebuster', '0')
-			->willReturn('15');
+			->method('getAppValueInt')
+			->with('cachebuster')
+			->willReturn(15);
 		$this->cacheFactory
 			->expects($this->exactly(2))
 			->method('createDistributed')
@@ -504,97 +505,106 @@ public function testSet(): void {
 	}
 
 	public function testUndoName(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
 			->method('deleteAppValue')
-			->with('theming', 'name');
-		$this->config
-			->expects($this->exactly(2))
-			->method('getAppValue')
-			->willReturnMap([
-				['theming', 'cachebuster', '0', '15'],
-				['theming', 'name', 'Nextcloud', 'Nextcloud'],
-			]);
-		$this->config
+			->with('name');
+		$this->appConfig
+			->expects($this->once())
+			->method('getAppValueInt')
+			->with('cachebuster')
+			->willReturn(15);
+		$this->appConfig
 			->expects($this->once())
-			->method('setAppValue')
-			->with('theming', 'cachebuster', 16);
+			->method('getAppValueString')
+			->with('name', 'Nextcloud')
+			->willReturn('Nextcloud');
+		$this->appConfig
+			->expects($this->once())
+			->method('setAppValueInt')
+			->with('cachebuster', 16);
 
 		$this->assertSame('Nextcloud', $this->template->undo('name'));
 	}
 
 	public function testUndoBaseUrl(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
 			->method('deleteAppValue')
-			->with('theming', 'url');
-		$this->config
-			->expects($this->exactly(2))
-			->method('getAppValue')
-			->willReturnMap([
-				['theming', 'cachebuster', '0', '15'],
-				['theming', 'url', $this->defaults->getBaseUrl(), $this->defaults->getBaseUrl()],
-			]);
-		$this->config
+			->with('url');
+		$this->appConfig
 			->expects($this->once())
-			->method('setAppValue')
-			->with('theming', 'cachebuster', 16);
+			->method('getAppValueInt')
+			->with('cachebuster')
+			->willReturn(15);
+		$this->appConfig
+			->expects($this->once())
+			->method('getAppValueString')
+			->with('url', $this->defaults->getBaseUrl())
+			->willReturn($this->defaults->getBaseUrl());
+		$this->appConfig
+			->expects($this->once())
+			->method('setAppValueInt')
+			->with('cachebuster', 16);
 
 		$this->assertSame($this->defaults->getBaseUrl(), $this->template->undo('url'));
 	}
 
 	public function testUndoSlogan(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
 			->method('deleteAppValue')
-			->with('theming', 'slogan');
-		$this->config
-			->expects($this->exactly(2))
-			->method('getAppValue')
-			->willReturnMap([
-				['theming', 'cachebuster', '0', '15'],
-				['theming', 'slogan', $this->defaults->getSlogan(), $this->defaults->getSlogan()],
-			]);
-		$this->config
+			->with('slogan');
+		$this->appConfig
+			->expects($this->once())
+			->method('getAppValueInt')
+			->with('cachebuster')
+			->willReturn(15);
+		$this->appConfig
 			->expects($this->once())
-			->method('setAppValue')
-			->with('theming', 'cachebuster', 16);
+			->method('getAppValueString')
+			->with('slogan', $this->defaults->getSlogan())
+			->willReturn($this->defaults->getSlogan());
+		$this->appConfig
+			->expects($this->once())
+			->method('setAppValueInt')
+			->with('cachebuster', 16);
 
 		$this->assertSame($this->defaults->getSlogan(), $this->template->undo('slogan'));
 	}
 
 	public function testUndoPrimaryColor(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
 			->method('deleteAppValue')
-			->with('theming', 'primary_color');
-		$this->config
+			->with('primary_color');
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'cachebuster', '0')
-			->willReturn('15');
-		$this->config
+			->method('getAppValueInt')
+			->with('cachebuster')
+			->willReturn(15);
+		$this->appConfig
 			->expects($this->once())
-			->method('setAppValue')
-			->with('theming', 'cachebuster', 16);
+			->method('setAppValueInt')
+			->with('cachebuster', 16);
 
 		$this->assertSame($this->defaults->getColorPrimary(), $this->template->undo('primary_color'));
 	}
 
 	public function testUndoDefaultAction(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
 			->method('deleteAppValue')
-			->with('theming', 'defaultitem');
-		$this->config
+			->with('defaultitem');
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'cachebuster', '0')
-			->willReturn('15');
-		$this->config
+			->method('getAppValueInt')
+			->with('cachebuster', '0')
+			->willReturn(15);
+		$this->appConfig
 			->expects($this->once())
-			->method('setAppValue')
-			->with('theming', 'cachebuster', 16);
+			->method('setAppValueInt')
+			->with('cachebuster', 16);
 
 		$this->assertSame('', $this->template->undo('defaultitem'));
 	}
@@ -613,13 +623,16 @@ private function getLogoHelper($withName, $useSvg) {
 			->method('getImage')
 			->with('logo')
 			->willThrowException(new NotFoundException());
-		$this->config
-			->expects($this->exactly(2))
-			->method('getAppValue')
-			->willReturnMap([
-				['theming', 'logoMime', '', ''],
-				['theming', 'cachebuster', '0', '0'],
-			]);
+		$this->appConfig
+			->expects($this->once())
+			->method('getAppValueString')
+			->with('logoMime', '')
+			->willReturn('');
+		$this->appConfig
+			->expects($this->once())
+			->method('getAppValueInt')
+			->with('cachebuster')
+			->willReturn(0);
 		$this->urlGenerator->expects($this->once())
 			->method('imagePath')
 			->with('core', $withName)
@@ -636,13 +649,16 @@ public function testGetLogoDefaultWithoutSvg(): void {
 	}
 
 	public function testGetLogoCustom(): void {
-		$this->config
-			->expects($this->exactly(2))
-			->method('getAppValue')
-			->willReturnMap([
-				['theming', 'logoMime', '', 'image/svg+xml'],
-				['theming', 'cachebuster', '0', '0'],
-			]);
+		$this->appConfig
+			->expects($this->once())
+			->method('getAppValueString')
+			->with('logoMime', '')
+			->willReturn('image/svg+xml');
+		$this->appConfig
+			->expects($this->once())
+			->method('getAppValueInt')
+			->with('cachebuster')
+			->willReturn(0);
 		$this->urlGenerator->expects($this->once())
 			->method('linkToRoute')
 			->with('theming.Theming.getImage')
@@ -651,7 +667,10 @@ public function testGetLogoCustom(): void {
 	}
 
 	public function testGetScssVariablesCached(): void {
-		$this->config->expects($this->any())->method('getAppValue')->with('theming', 'cachebuster', '0')->willReturn('1');
+		$this->appConfig->expects($this->any())
+			->method('getAppValueInt')
+			->with('cachebuster')
+			->willReturn(1);
 		$this->cacheFactory->expects($this->once())
 			->method('createDistributed')
 			->with('theming-1-')
@@ -661,23 +680,22 @@ public function testGetScssVariablesCached(): void {
 	}
 
 	public function testGetScssVariables(): void {
-		$this->config
-			->expects($this->any())
-			->method('getAppValue')
-			->willReturnMap([
-				['theming', 'cachebuster', '0', '0'],
-				['theming', 'logoMime', '', 'jpeg'],
-				['theming', 'backgroundMime', '', 'jpeg'],
-				['theming', 'logoheaderMime', '', 'jpeg'],
-				['theming', 'faviconMime', '', 'jpeg'],
-			]);
-
+		$this->appConfig->expects($this->any())
+			->method('getAppValueInt')
+			->with('cachebuster')
+			->willReturn(0);
 		$this->appConfig
-			->expects(self::atLeastOnce())
-			->method('getValueString')
+			->expects($this->any())
+			->method('getAppValueString')
 			->willReturnMap([
-				['theming', 'primary_color', '', false, $this->defaults->getColorPrimary()],
-				['theming', 'primary_color', $this->defaults->getColorPrimary(), false, $this->defaults->getColorPrimary()],
+				['imprintUrl', '', ''],
+				['privacyUrl', '', ''],
+				['logoMime', '', 'jpeg'],
+				['backgroundMime', '', 'jpeg'],
+				['logoheaderMime', '', 'jpeg'],
+				['faviconMime', '', 'jpeg'],
+				['primary_color', '', false, $this->defaults->getColorPrimary()],
+				['primary_color', $this->defaults->getColorPrimary(), false, $this->defaults->getColorPrimary()],
 			]);
 
 		$this->util->expects($this->any())->method('invertTextColor')->with($this->defaults->getColorPrimary())->willReturn(false);
@@ -716,60 +734,60 @@ public function testGetScssVariables(): void {
 	}
 
 	public function testGetDefaultAndroidURL(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'AndroidClientUrl', 'https://play.google.com/store/apps/details?id=com.nextcloud.client')
+			->method('getAppValueString')
+			->with('AndroidClientUrl', 'https://play.google.com/store/apps/details?id=com.nextcloud.client')
 			->willReturn('https://play.google.com/store/apps/details?id=com.nextcloud.client');
 
 		$this->assertEquals('https://play.google.com/store/apps/details?id=com.nextcloud.client', $this->template->getAndroidClientUrl());
 	}
 
 	public function testGetCustomAndroidURL(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'AndroidClientUrl', 'https://play.google.com/store/apps/details?id=com.nextcloud.client')
+			->method('getAppValueString')
+			->with('AndroidClientUrl', 'https://play.google.com/store/apps/details?id=com.nextcloud.client')
 			->willReturn('https://play.google.com/store/apps/details?id=com.mycloud.client');
 
 		$this->assertEquals('https://play.google.com/store/apps/details?id=com.mycloud.client', $this->template->getAndroidClientUrl());
 	}
 
 	public function testGetDefaultiOSURL(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'iOSClientUrl', 'https://geo.itunes.apple.com/us/app/nextcloud/id1125420102?mt=8')
+			->method('getAppValueString')
+			->with('iOSClientUrl', 'https://geo.itunes.apple.com/us/app/nextcloud/id1125420102?mt=8')
 			->willReturn('https://geo.itunes.apple.com/us/app/nextcloud/id1125420102?mt=8');
 
 		$this->assertEquals('https://geo.itunes.apple.com/us/app/nextcloud/id1125420102?mt=8', $this->template->getiOSClientUrl());
 	}
 
 	public function testGetCustomiOSURL(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'iOSClientUrl', 'https://geo.itunes.apple.com/us/app/nextcloud/id1125420102?mt=8')
+			->method('getAppValueString')
+			->with('iOSClientUrl', 'https://geo.itunes.apple.com/us/app/nextcloud/id1125420102?mt=8')
 			->willReturn('https://geo.itunes.apple.com/us/app/nextcloud/id1234567890?mt=8');
 
 		$this->assertEquals('https://geo.itunes.apple.com/us/app/nextcloud/id1234567890?mt=8', $this->template->getiOSClientUrl());
 	}
 
 	public function testGetDefaultiTunesAppId(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'iTunesAppId', '1125420102')
+			->method('getAppValueString')
+			->with('iTunesAppId', '1125420102')
 			->willReturn('1125420102');
 
 		$this->assertEquals('1125420102', $this->template->getiTunesAppId());
 	}
 
 	public function testGetCustomiTunesAppId(): void {
-		$this->config
+		$this->appConfig
 			->expects($this->once())
-			->method('getAppValue')
-			->with('theming', 'iTunesAppId', '1125420102')
+			->method('getAppValueString')
+			->with('iTunesAppId', '1125420102')
 			->willReturn('1234567890');
 
 		$this->assertEquals('1234567890', $this->template->getiTunesAppId());
@@ -790,11 +808,11 @@ public function testReplaceImagePath(string $app, string $image, string|bool $re
 			->method('get')
 			->with('shouldReplaceIcons')
 			->willReturn(true);
-		$this->config
+		$this->appConfig
 			->expects($this->any())
-			->method('getAppValue')
-			->with('theming', 'cachebuster', '0')
-			->willReturn('0');
+			->method('getAppValueInt')
+			->with('cachebuster')
+			->willReturn(0);
 		$this->urlGenerator
 			->expects($this->any())
 			->method('linkToRoute')
diff --git a/build/psalm-baseline.xml b/build/psalm-baseline.xml
index 7e3f9ab604ce3..a739d12529e63 100644
--- a/build/psalm-baseline.xml
+++ b/build/psalm-baseline.xml
@@ -2584,40 +2584,6 @@
       <code><![CDATA[getAppValue]]></code>
     </DeprecatedMethod>
   </file>
-  <file src="apps/theming/lib/ThemingDefaults.php">
-    <DeprecatedMethod>
-      <code><![CDATA[deleteAppValue]]></code>
-      <code><![CDATA[deleteAppValue]]></code>
-      <code><![CDATA[deleteAppValues]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[getAppValue]]></code>
-      <code><![CDATA[setAppValue]]></code>
-      <code><![CDATA[setAppValue]]></code>
-    </DeprecatedMethod>
-  </file>
   <file src="apps/theming/lib/Util.php">
     <DeprecatedMethod>
       <code><![CDATA[getAppValue]]></code>
diff --git a/lib/private/Server.php b/lib/private/Server.php
index 927d2ce322422..5b92d0f9a09a2 100644
--- a/lib/private/Server.php
+++ b/lib/private/Server.php
@@ -15,6 +15,7 @@
 use OC\AppFramework\Bootstrap\Coordinator;
 use OC\AppFramework\Http\Request;
 use OC\AppFramework\Http\RequestId;
+use OC\AppFramework\Services\AppConfig;
 use OC\AppFramework\Utility\TimeFactory;
 use OC\Authentication\Events\LoginFailed;
 use OC\Authentication\Listeners\LoginFailedListener;
@@ -150,6 +151,7 @@
 use OCP\Federation\ICloudFederationFactory;
 use OCP\Federation\ICloudFederationProviderManager;
 use OCP\Federation\ICloudIdManager;
+use OCP\Files\AppData\IAppDataFactory;
 use OCP\Files\Cache\IFileAccess;
 use OCP\Files\Config\IMountProviderCollection;
 use OCP\Files\Config\IUserMountCache;
@@ -1009,14 +1011,14 @@ public function __construct($webRoot, \OC\Config $config) {
 			if ($classExists && $c->get(\OCP\IConfig::class)->getSystemValueBool('installed', false) && $c->get(IAppManager::class)->isEnabledForAnyone('theming') && $c->get(TrustedDomainHelper::class)->isTrustedDomain($c->getRequest()->getInsecureServerHost())) {
 				$backgroundService = new BackgroundService(
 					$c->get(IRootFolder::class),
-					$c->getAppDataDir('theming'),
+					$c->get(IAppDataFactory::class)->get('theming'),
 					$c->get(IAppConfig::class),
 					$c->get(\OCP\IConfig::class),
 					$c->get(ISession::class)->get('user_id'),
 				);
 				$imageManager = new ImageManager(
 					$c->get(\OCP\IConfig::class),
-					$c->getAppDataDir('theming'),
+					$c->get(IAppDataFactory::class)->get('theming'),
 					$c->get(IURLGenerator::class),
 					$c->get(ICacheFactory::class),
 					$c->get(LoggerInterface::class),
@@ -1025,12 +1027,22 @@ public function __construct($webRoot, \OC\Config $config) {
 				);
 				return new ThemingDefaults(
 					$c->get(\OCP\IConfig::class),
-					$c->get(\OCP\IAppConfig::class),
-					$c->getL10N('theming'),
+					new AppConfig(
+						$c->get(\OCP\IConfig::class),
+						$c->get(\OCP\IAppConfig::class),
+						'theming',
+					),
+					$c->get(IFactory::class)->get('theming'),
 					$c->get(IUserSession::class),
 					$c->get(IURLGenerator::class),
 					$c->get(ICacheFactory::class),
-					new Util($c->get(ServerVersion::class), $c->get(\OCP\IConfig::class), $this->get(IAppManager::class), $c->getAppDataDir('theming'), $imageManager),
+					new Util(
+						$c->get(ServerVersion::class),
+						$c->get(\OCP\IConfig::class),
+						$this->get(IAppManager::class),
+						$c->get(IAppDataFactory::class)->get('theming'),
+						$imageManager,
+					),
 					$imageManager,
 					$c->get(IAppManager::class),
 					$c->get(INavigationManager::class),