diff --git a/lib/private/PreviewManager.php b/lib/private/PreviewManager.php
index aedcbbce335fc..7630f2ec30a89 100644
--- a/lib/private/PreviewManager.php
+++ b/lib/private/PreviewManager.php
@@ -180,7 +180,7 @@ private function getGenerator(): Generator {
 	 * @throws \InvalidArgumentException if the preview would be invalid (in case the original image is invalid)
 	 * @since 11.0.0 - \InvalidArgumentException was added in 12.0.0
 	 */
-	public function getPreview(File $file, $width = -1, $height = -1, $crop = false, $mode = IPreview::MODE_FILL, $mimeType = null) {
+	public function getPreview(File $file, $width = -1, $height = -1, $crop = false, $mode = IPreview::MODE_FILL, $mimeType = null): ISimpleFile {
 		$previewConcurrency = $this->getGenerator()->getNumConcurrentPreviews('preview_concurrency_all');
 		$sem = Generator::guardWithSemaphore(Generator::SEMAPHORE_ID_ALL, $previewConcurrency);
 		try {
@@ -203,7 +203,7 @@ public function getPreview(File $file, $width = -1, $height = -1, $crop = false,
 	 * @throws \InvalidArgumentException if the preview would be invalid (in case the original image is invalid)
 	 * @since 19.0.0
 	 */
-	public function generatePreviews(File $file, array $specifications, $mimeType = null) {
+	public function generatePreviews(File $file, array $specifications, $mimeType = null): ISimpleFile {
 		return $this->getGenerator()->generatePreviews($file, $specifications, $mimeType);
 	}
 
@@ -213,7 +213,7 @@ public function generatePreviews(File $file, array $specifications, $mimeType =
 	 * @param string $mimeType
 	 * @return boolean
 	 */
-	public function isMimeSupported($mimeType = '*') {
+	public function isMimeSupported($mimeType = '*'): bool {
 		if (!$this->config->getSystemValueBool('enable_previews', true)) {
 			return false;
 		}
@@ -299,9 +299,9 @@ public function isAvailable(\OCP\Files\FileInfo $file): bool {
 	 *  - OC\Preview\SVG
 	 *  - OC\Preview\TIFF
 	 *
-	 * @return array
+	 * @return array|null
 	 */
-	protected function getEnabledDefaultProvider() {
+	protected function getEnabledDefaultProvider(): ?array {
 		if ($this->defaultProviders !== null) {
 			return $this->defaultProviders;
 		}
@@ -335,8 +335,9 @@ protected function getEnabledDefaultProvider() {
 	 *
 	 * @param string $class
 	 * @param string $mimeType
+	 * @param array $options
 	 */
-	protected function registerCoreProvider($class, $mimeType, $options = []) {
+	protected function registerCoreProvider(string $class, string $mimeType, array $options = []): void {
 		if (in_array(trim($class, '\\'), $this->getEnabledDefaultProvider())) {
 			$this->registerProvider($mimeType, function () use ($class, $options) {
 				return new $class($options);
@@ -347,7 +348,7 @@ protected function registerCoreProvider($class, $mimeType, $options = []) {
 	/**
 	 * Register the default providers (if enabled)
 	 */
-	protected function registerCoreProviders() {
+	protected function registerCoreProviders(): void {
 		if ($this->registeredCoreProviders) {
 			return;
 		}
diff --git a/lib/private/RedisFactory.php b/lib/private/RedisFactory.php
index 4903a8713df2e..21aa077caa09d 100644
--- a/lib/private/RedisFactory.php
+++ b/lib/private/RedisFactory.php
@@ -33,23 +33,23 @@ class RedisFactory {
 	public const REDIS_EXTRA_PARAMETERS_MINIMAL_VERSION = '5.3.0';
 
 	/** @var  \Redis|\RedisCluster */
-	private $instance;
-
-	private SystemConfig $config;
-
-	private IEventLogger $eventLogger;
+	private \Redis|\RedisCluster $instance;
 
 	/**
 	 * RedisFactory constructor.
 	 *
 	 * @param SystemConfig $config
 	 */
-	public function __construct(SystemConfig $config, IEventLogger $eventLogger) {
-		$this->config = $config;
-		$this->eventLogger = $eventLogger;
+	public function __construct(
+		private SystemConfig $config,
+		private IEventLogger $eventLogger,
+	) {
 	}
 
-	private function create() {
+	/**
+	 * @throws \Exception
+	 */
+	private function create(): void {
 		$isCluster = in_array('redis.cluster', $this->config->getKeys(), true);
 		$config = $isCluster
 			? $this->config->getValue('redis.cluster', [])
@@ -137,7 +137,7 @@ private function create() {
 	 * @return array|null
 	 * @throws \UnexpectedValueException
 	 */
-	private function getSslContext($config) {
+	private function getSslContext(array $config): ?array {
 		if (isset($config['ssl_context'])) {
 			if (!$this->isConnectionParametersSupported()) {
 				throw new \UnexpectedValueException(\sprintf(
@@ -150,7 +150,10 @@ private function getSslContext($config) {
 		return null;
 	}
 
-	public function getInstance() {
+	/**
+	 * @throws \Exception
+	 */
+	public function getInstance(): \RedisCluster|\Redis {
 		if (!$this->isAvailable()) {
 			throw new \Exception('Redis support is not available');
 		}
diff --git a/lib/private/Repair.php b/lib/private/Repair.php
index b1800d6087d39..bbd5e5f6a12b2 100644
--- a/lib/private/Repair.php
+++ b/lib/private/Repair.php
@@ -110,7 +110,7 @@ public function setRepairSteps(array $repairSteps): void {
 	/**
 	 * Run a series of repair steps for common problems
 	 */
-	public function run() {
+	public function run(): void {
 		if (count($this->repairSteps) === 0) {
 			$this->dispatcher->dispatchTyped(new RepairInfoEvent('No repair steps available'));
 
@@ -132,10 +132,10 @@ public function run() {
 	/**
 	 * Add repair step
 	 *
-	 * @param IRepairStep|string $repairStep repair step
+	 * @param string|IRepairStep $repairStep repair step
 	 * @throws \Exception
 	 */
-	public function addStep($repairStep) {
+	public function addStep(string|IRepairStep $repairStep): void {
 		if (is_string($repairStep)) {
 			try {
 				$s = \OC::$server->get($repairStep);
@@ -220,7 +220,7 @@ public static function getRepairSteps(): array {
 	 *
 	 * @return IRepairStep[]
 	 */
-	public static function getExpensiveRepairSteps() {
+	public static function getExpensiveRepairSteps(): array {
 		return [
 			new OldGroupMembershipShares(\OC::$server->getDatabaseConnection(), \OC::$server->getGroupManager()),
 			\OC::$server->get(ValidatePhoneNumber::class),
@@ -233,7 +233,7 @@ public static function getExpensiveRepairSteps() {
 	 *
 	 * @return IRepairStep[]
 	 */
-	public static function getBeforeUpgradeRepairSteps() {
+	public static function getBeforeUpgradeRepairSteps(): array {
 		/** @var ConnectionAdapter $connectionAdapter */
 		$connectionAdapter = \OC::$server->get(ConnectionAdapter::class);
 		$config = \OC::$server->getConfig();
@@ -252,7 +252,7 @@ public function debug(string $message): void {
 	/**
 	 * @param string $message
 	 */
-	public function info($message) {
+	public function info($message): void {
 		// for now just emit as we did in the past
 		$this->dispatcher->dispatchTyped(new RepairInfoEvent($message));
 	}
@@ -260,7 +260,7 @@ public function info($message) {
 	/**
 	 * @param string $message
 	 */
-	public function warning($message) {
+	public function warning($message): void {
 		// for now just emit as we did in the past
 		$this->dispatcher->dispatchTyped(new RepairWarningEvent($message));
 	}
@@ -268,7 +268,7 @@ public function warning($message) {
 	/**
 	 * @param int $max
 	 */
-	public function startProgress($max = 0) {
+	public function startProgress($max = 0): void {
 		// for now just emit as we did in the past
 		$this->dispatcher->dispatchTyped(new RepairStartEvent($max, $this->currentStep));
 	}
@@ -277,15 +277,12 @@ public function startProgress($max = 0) {
 	 * @param int $step number of step to advance
 	 * @param string $description
 	 */
-	public function advance($step = 1, $description = '') {
+	public function advance($step = 1, $description = ''): void {
 		// for now just emit as we did in the past
 		$this->dispatcher->dispatchTyped(new RepairAdvanceEvent($step, $description));
 	}
 
-	/**
-	 * @param int $max
-	 */
-	public function finishProgress() {
+	public function finishProgress(): void {
 		// for now just emit as we did in the past
 		$this->dispatcher->dispatchTyped(new RepairFinishEvent());
 	}
diff --git a/lib/private/Search.php b/lib/private/Search.php
index 9f1a0323aa30b..145601e832688 100644
--- a/lib/private/Search.php
+++ b/lib/private/Search.php
@@ -37,8 +37,8 @@
  */
 class Search implements ISearch {
 	/** @var Provider[] */
-	private $providers = [];
-	private $registeredProviders = [];
+	private array $providers = [];
+	private array $registeredProviders = [];
 
 	/**
 	 * Search all providers for $query
@@ -48,7 +48,7 @@ class Search implements ISearch {
 	 * @param int $size, 0 = all
 	 * @return array An array of OC\Search\Result's
 	 */
-	public function searchPaged($query, array $inApps = [], $page = 1, $size = 30) {
+	public function searchPaged($query, array $inApps = [], $page = 1, $size = 30): array {
 		$this->initProviders();
 		$results = [];
 		foreach ($this->providers as $provider) {
@@ -75,7 +75,7 @@ public function searchPaged($query, array $inApps = [], $page = 1, $size = 30) {
 	/**
 	 * Remove all registered search providers
 	 */
-	public function clearProviders() {
+	public function clearProviders(): void {
 		$this->providers = [];
 		$this->registeredProviders = [];
 	}
@@ -84,7 +84,7 @@ public function clearProviders() {
 	 * Remove one existing search provider
 	 * @param string $provider class name of a OC\Search\Provider
 	 */
-	public function removeProvider($provider) {
+	public function removeProvider($provider): void {
 		$this->registeredProviders = array_filter(
 			$this->registeredProviders,
 			function ($element) use ($provider) {
@@ -100,14 +100,14 @@ function ($element) use ($provider) {
 	 * @param string $class class name of a OC\Search\Provider
 	 * @param array $options optional
 	 */
-	public function registerProvider($class, array $options = []) {
+	public function registerProvider($class, array $options = []): void {
 		$this->registeredProviders[] = ['class' => $class, 'options' => $options];
 	}
 
 	/**
 	 * Create instances of all the registered search providers
 	 */
-	private function initProviders() {
+	private function initProviders(): void {
 		if (! empty($this->providers)) {
 			return;
 		}
diff --git a/lib/private/Server.php b/lib/private/Server.php
index 21d60d558295a..333458a7c5336 100644
--- a/lib/private/Server.php
+++ b/lib/private/Server.php
@@ -292,16 +292,15 @@
  * TODO: hookup all manager classes
  */
 class Server extends ServerContainer implements IServerContainer {
-	/** @var string */
-	private $webRoot;
-
 	/**
 	 * @param string $webRoot
 	 * @param \OC\Config $config
 	 */
-	public function __construct($webRoot, \OC\Config $config) {
+	public function __construct(
+		private string $webRoot,
+		\OC\Config $config,
+	) {
 		parent::__construct();
-		$this->webRoot = $webRoot;
 
 		// To find out if we are running from CLI or not
 		$this->registerParameter('isCLI', \OC::$CLI);
@@ -1436,7 +1435,7 @@ public function __construct($webRoot, \OC\Config $config) {
 		$this->connectDispatcher();
 	}
 
-	public function boot() {
+	public function boot(): void {
 		/** @var HookConnector $hookConnector */
 		$hookConnector = $this->get(HookConnector::class);
 		$hookConnector->viewToNode();
@@ -1446,7 +1445,7 @@ public function boot() {
 	 * @return \OCP\Calendar\IManager
 	 * @deprecated 20.0.0
 	 */
-	public function getCalendarManager() {
+	public function getCalendarManager(): \OCP\Calendar\IManager {
 		return $this->get(\OC\Calendar\Manager::class);
 	}
 
@@ -1454,7 +1453,7 @@ public function getCalendarManager() {
 	 * @return \OCP\Calendar\Resource\IManager
 	 * @deprecated 20.0.0
 	 */
-	public function getCalendarResourceBackendManager() {
+	public function getCalendarResourceBackendManager(): \OCP\Calendar\Resource\IManager {
 		return $this->get(\OC\Calendar\Resource\Manager::class);
 	}
 
@@ -1462,7 +1461,7 @@ public function getCalendarResourceBackendManager() {
 	 * @return \OCP\Calendar\Room\IManager
 	 * @deprecated 20.0.0
 	 */
-	public function getCalendarRoomBackendManager() {
+	public function getCalendarRoomBackendManager(): \OCP\Calendar\Room\IManager {
 		return $this->get(\OC\Calendar\Room\Manager::class);
 	}
 
@@ -1482,7 +1481,7 @@ private function connectDispatcher(): void {
 	 * @return \OCP\Contacts\IManager
 	 * @deprecated 20.0.0
 	 */
-	public function getContactsManager() {
+	public function getContactsManager(): \OCP\Contacts\IManager {
 		return $this->get(\OCP\Contacts\IManager::class);
 	}
 
@@ -1490,7 +1489,7 @@ public function getContactsManager() {
 	 * @return \OC\Encryption\Manager
 	 * @deprecated 20.0.0
 	 */
-	public function getEncryptionManager() {
+	public function getEncryptionManager(): Encryption\Manager {
 		return $this->get(\OCP\Encryption\IManager::class);
 	}
 
@@ -1498,7 +1497,7 @@ public function getEncryptionManager() {
 	 * @return \OC\Encryption\File
 	 * @deprecated 20.0.0
 	 */
-	public function getEncryptionFilesHelper() {
+	public function getEncryptionFilesHelper(): Encryption\File {
 		return $this->get(IFile::class);
 	}
 
@@ -1506,7 +1505,7 @@ public function getEncryptionFilesHelper() {
 	 * @return \OCP\Encryption\Keys\IStorage
 	 * @deprecated 20.0.0
 	 */
-	public function getEncryptionKeyStorage() {
+	public function getEncryptionKeyStorage(): IStorage {
 		return $this->get(IStorage::class);
 	}
 
@@ -1518,7 +1517,7 @@ public function getEncryptionKeyStorage() {
 	 * @return \OCP\IRequest
 	 * @deprecated 20.0.0
 	 */
-	public function getRequest() {
+	public function getRequest(): IRequest {
 		return $this->get(IRequest::class);
 	}
 
@@ -1528,7 +1527,7 @@ public function getRequest() {
 	 * @return IPreview
 	 * @deprecated 20.0.0
 	 */
-	public function getPreviewManager() {
+	public function getPreviewManager(): IPreview {
 		return $this->get(IPreview::class);
 	}
 
@@ -1539,7 +1538,7 @@ public function getPreviewManager() {
 	 * @return ITagManager
 	 * @deprecated 20.0.0
 	 */
-	public function getTagManager() {
+	public function getTagManager(): ITagManager {
 		return $this->get(ITagManager::class);
 	}
 
@@ -1551,7 +1550,7 @@ public function getTagManager() {
 	 * @since 9.0.0
 	 * @deprecated 20.0.0
 	 */
-	public function getSystemTagManager() {
+	public function getSystemTagManager(): ISystemTagManager {
 		return $this->get(ISystemTagManager::class);
 	}
 
@@ -1563,7 +1562,7 @@ public function getSystemTagManager() {
 	 * @since 9.0.0
 	 * @deprecated 20.0.0
 	 */
-	public function getSystemTagObjectMapper() {
+	public function getSystemTagObjectMapper(): ISystemTagObjectMapper {
 		return $this->get(ISystemTagObjectMapper::class);
 	}
 
@@ -1573,7 +1572,7 @@ public function getSystemTagObjectMapper() {
 	 * @return IAvatarManager
 	 * @deprecated 20.0.0
 	 */
-	public function getAvatarManager() {
+	public function getAvatarManager(): IAvatarManager {
 		return $this->get(IAvatarManager::class);
 	}
 
@@ -1583,7 +1582,7 @@ public function getAvatarManager() {
 	 * @return IRootFolder
 	 * @deprecated 20.0.0
 	 */
-	public function getRootFolder() {
+	public function getRootFolder(): IRootFolder {
 		return $this->get(IRootFolder::class);
 	}
 
@@ -1595,7 +1594,7 @@ public function getRootFolder() {
 	 * @return IRootFolder
 	 * @deprecated 20.0.0
 	 */
-	public function getLazyRootFolder() {
+	public function getLazyRootFolder(): IRootFolder {
 		return $this->get(IRootFolder::class);
 	}
 
@@ -1606,7 +1605,7 @@ public function getLazyRootFolder() {
 	 * @return \OCP\Files\Folder|null
 	 * @deprecated 20.0.0
 	 */
-	public function getUserFolder($userId = null) {
+	public function getUserFolder($userId = null): ?\OCP\Files\Folder {
 		if ($userId === null) {
 			$user = $this->get(IUserSession::class)->getUser();
 			if (!$user) {
@@ -1622,7 +1621,7 @@ public function getUserFolder($userId = null) {
 	 * @return \OC\User\Manager
 	 * @deprecated 20.0.0
 	 */
-	public function getUserManager() {
+	public function getUserManager(): User\Manager {
 		return $this->get(IUserManager::class);
 	}
 
@@ -1630,7 +1629,7 @@ public function getUserManager() {
 	 * @return \OC\Group\Manager
 	 * @deprecated 20.0.0
 	 */
-	public function getGroupManager() {
+	public function getGroupManager(): Group\Manager {
 		return $this->get(IGroupManager::class);
 	}
 
@@ -1638,7 +1637,7 @@ public function getGroupManager() {
 	 * @return \OC\User\Session
 	 * @deprecated 20.0.0
 	 */
-	public function getUserSession() {
+	public function getUserSession(): Session {
 		return $this->get(IUserSession::class);
 	}
 
@@ -1646,7 +1645,7 @@ public function getUserSession() {
 	 * @return \OCP\ISession
 	 * @deprecated 20.0.0
 	 */
-	public function getSession() {
+	public function getSession(): ISession {
 		return $this->get(Session::class)->getSession();
 	}
 
@@ -1654,7 +1653,7 @@ public function getSession() {
 	 * @param \OCP\ISession $session
 	 * @return void
 	 */
-	public function setSession(\OCP\ISession $session) {
+	public function setSession(\OCP\ISession $session): void {
 		$this->get(SessionStorage::class)->setSession($session);
 		$this->get(Session::class)->setSession($session);
 		$this->get(Store::class)->setSession($session);
@@ -1664,7 +1663,7 @@ public function setSession(\OCP\ISession $session) {
 	 * @return \OC\Authentication\TwoFactorAuth\Manager
 	 * @deprecated 20.0.0
 	 */
-	public function getTwoFactorAuthManager() {
+	public function getTwoFactorAuthManager(): Authentication\TwoFactorAuth\Manager {
 		return $this->get(\OC\Authentication\TwoFactorAuth\Manager::class);
 	}
 
@@ -1672,7 +1671,7 @@ public function getTwoFactorAuthManager() {
 	 * @return \OC\NavigationManager
 	 * @deprecated 20.0.0
 	 */
-	public function getNavigationManager() {
+	public function getNavigationManager(): NavigationManager {
 		return $this->get(INavigationManager::class);
 	}
 
@@ -1680,7 +1679,7 @@ public function getNavigationManager() {
 	 * @return \OCP\IConfig
 	 * @deprecated 20.0.0
 	 */
-	public function getConfig() {
+	public function getConfig(): \OCP\IConfig {
 		return $this->get(AllConfig::class);
 	}
 
@@ -1688,7 +1687,7 @@ public function getConfig() {
 	 * @return \OC\SystemConfig
 	 * @deprecated 20.0.0
 	 */
-	public function getSystemConfig() {
+	public function getSystemConfig(): SystemConfig {
 		return $this->get(SystemConfig::class);
 	}
 
@@ -1698,7 +1697,7 @@ public function getSystemConfig() {
 	 * @return IAppConfig
 	 * @deprecated 20.0.0
 	 */
-	public function getAppConfig() {
+	public function getAppConfig(): IAppConfig {
 		return $this->get(IAppConfig::class);
 	}
 
@@ -1706,7 +1705,7 @@ public function getAppConfig() {
 	 * @return IFactory
 	 * @deprecated 20.0.0
 	 */
-	public function getL10NFactory() {
+	public function getL10NFactory(): IFactory {
 		return $this->get(IFactory::class);
 	}
 
@@ -1718,7 +1717,7 @@ public function getL10NFactory() {
 	 * @return IL10N
 	 * @deprecated 20.0.0 use DI of {@see IL10N} or {@see IFactory} instead, or {@see \OCP\Util::getL10N()} as a last resort
 	 */
-	public function getL10N($app, $lang = null) {
+	public function getL10N($app, $lang = null): IL10N {
 		return $this->get(IFactory::class)->get($app, $lang);
 	}
 
@@ -1726,7 +1725,7 @@ public function getL10N($app, $lang = null) {
 	 * @return IURLGenerator
 	 * @deprecated 20.0.0
 	 */
-	public function getURLGenerator() {
+	public function getURLGenerator(): IURLGenerator {
 		return $this->get(IURLGenerator::class);
 	}
 
@@ -1734,7 +1733,7 @@ public function getURLGenerator() {
 	 * @return AppFetcher
 	 * @deprecated 20.0.0
 	 */
-	public function getAppFetcher() {
+	public function getAppFetcher(): AppFetcher {
 		return $this->get(AppFetcher::class);
 	}
 
@@ -1745,7 +1744,7 @@ public function getAppFetcher() {
 	 * @return ICache
 	 * @deprecated 8.1.0 use getMemCacheFactory to obtain a proper cache
 	 */
-	public function getCache() {
+	public function getCache(): ICache {
 		return $this->get(ICache::class);
 	}
 
@@ -1755,7 +1754,7 @@ public function getCache() {
 	 * @return \OCP\ICacheFactory
 	 * @deprecated 20.0.0
 	 */
-	public function getMemCacheFactory() {
+	public function getMemCacheFactory(): ICacheFactory {
 		return $this->get(ICacheFactory::class);
 	}
 
@@ -1765,7 +1764,7 @@ public function getMemCacheFactory() {
 	 * @return \OC\RedisFactory
 	 * @deprecated 20.0.0
 	 */
-	public function getGetRedisFactory() {
+	public function getGetRedisFactory(): RedisFactory {
 		return $this->get('RedisFactory');
 	}
 
@@ -1776,7 +1775,7 @@ public function getGetRedisFactory() {
 	 * @return \OCP\IDBConnection
 	 * @deprecated 20.0.0
 	 */
-	public function getDatabaseConnection() {
+	public function getDatabaseConnection(): IDBConnection {
 		return $this->get(IDBConnection::class);
 	}
 
@@ -1786,7 +1785,7 @@ public function getDatabaseConnection() {
 	 * @return \OCP\Activity\IManager
 	 * @deprecated 20.0.0
 	 */
-	public function getActivityManager() {
+	public function getActivityManager(): \OCP\Activity\IManager {
 		return $this->get(\OCP\Activity\IManager::class);
 	}
 
@@ -1796,7 +1795,7 @@ public function getActivityManager() {
 	 * @return IJobList
 	 * @deprecated 20.0.0
 	 */
-	public function getJobList() {
+	public function getJobList(): IJobList {
 		return $this->get(IJobList::class);
 	}
 
@@ -1806,7 +1805,7 @@ public function getJobList() {
 	 * @return ILogger
 	 * @deprecated 20.0.0
 	 */
-	public function getLogger() {
+	public function getLogger(): ILogger {
 		return $this->get(ILogger::class);
 	}
 
@@ -1815,7 +1814,7 @@ public function getLogger() {
 	 * @throws \OCP\AppFramework\QueryException
 	 * @deprecated 20.0.0
 	 */
-	public function getLogFactory() {
+	public function getLogFactory(): ILogFactory {
 		return $this->get(ILogFactory::class);
 	}
 
@@ -1825,7 +1824,7 @@ public function getLogFactory() {
 	 * @return IRouter
 	 * @deprecated 20.0.0
 	 */
-	public function getRouter() {
+	public function getRouter(): IRouter {
 		return $this->get(IRouter::class);
 	}
 
@@ -1835,7 +1834,7 @@ public function getRouter() {
 	 * @return ISearch
 	 * @deprecated 20.0.0
 	 */
-	public function getSearch() {
+	public function getSearch(): ISearch {
 		return $this->get(ISearch::class);
 	}
 
@@ -1845,7 +1844,7 @@ public function getSearch() {
 	 * @return \OCP\Security\ISecureRandom
 	 * @deprecated 20.0.0
 	 */
-	public function getSecureRandom() {
+	public function getSecureRandom(): ISecureRandom {
 		return $this->get(ISecureRandom::class);
 	}
 
@@ -1855,7 +1854,7 @@ public function getSecureRandom() {
 	 * @return ICrypto
 	 * @deprecated 20.0.0
 	 */
-	public function getCrypto() {
+	public function getCrypto(): ICrypto {
 		return $this->get(ICrypto::class);
 	}
 
@@ -1865,7 +1864,7 @@ public function getCrypto() {
 	 * @return IHasher
 	 * @deprecated 20.0.0
 	 */
-	public function getHasher() {
+	public function getHasher(): IHasher {
 		return $this->get(IHasher::class);
 	}
 
@@ -1875,7 +1874,7 @@ public function getHasher() {
 	 * @return ICredentialsManager
 	 * @deprecated 20.0.0
 	 */
-	public function getCredentialsManager() {
+	public function getCredentialsManager(): ICredentialsManager {
 		return $this->get(ICredentialsManager::class);
 	}
 
@@ -1884,7 +1883,7 @@ public function getCredentialsManager() {
 	 *
 	 * @return \OCP\ICertificateManager
 	 */
-	public function getCertificateManager() {
+	public function getCertificateManager(): ICertificateManager {
 		return $this->get(ICertificateManager::class);
 	}
 
@@ -1894,7 +1893,7 @@ public function getCertificateManager() {
 	 * @return IClientService
 	 * @deprecated 20.0.0
 	 */
-	public function getHTTPClientService() {
+	public function getHTTPClientService(): IClientService {
 		return $this->get(IClientService::class);
 	}
 
@@ -1906,7 +1905,7 @@ public function getHTTPClientService() {
 	 * @return IEventLogger
 	 * @deprecated 20.0.0
 	 */
-	public function getEventLogger() {
+	public function getEventLogger(): IEventLogger {
 		return $this->get(IEventLogger::class);
 	}
 
@@ -1918,7 +1917,7 @@ public function getEventLogger() {
 	 * @return IQueryLogger
 	 * @deprecated 20.0.0
 	 */
-	public function getQueryLogger() {
+	public function getQueryLogger(): IQueryLogger {
 		return $this->get(IQueryLogger::class);
 	}
 
@@ -1928,7 +1927,7 @@ public function getQueryLogger() {
 	 * @return \OCP\ITempManager
 	 * @deprecated 20.0.0
 	 */
-	public function getTempManager() {
+	public function getTempManager(): ITempManager {
 		return $this->get(ITempManager::class);
 	}
 
@@ -1938,7 +1937,7 @@ public function getTempManager() {
 	 * @return \OCP\App\IAppManager
 	 * @deprecated 20.0.0
 	 */
-	public function getAppManager() {
+	public function getAppManager(): IAppManager {
 		return $this->get(IAppManager::class);
 	}
 
@@ -1948,7 +1947,7 @@ public function getAppManager() {
 	 * @return IMailer
 	 * @deprecated 20.0.0
 	 */
-	public function getMailer() {
+	public function getMailer(): IMailer {
 		return $this->get(IMailer::class);
 	}
 
@@ -1958,7 +1957,7 @@ public function getMailer() {
 	 * @return string
 	 * @deprecated 20.0.0
 	 */
-	public function getWebRoot() {
+	public function getWebRoot(): string {
 		return $this->webRoot;
 	}
 
@@ -1974,7 +1973,7 @@ public function getOcsClient() {
 	 * @return IDateTimeZone
 	 * @deprecated 20.0.0
 	 */
-	public function getDateTimeZone() {
+	public function getDateTimeZone(): IDateTimeZone {
 		return $this->get(IDateTimeZone::class);
 	}
 
@@ -1982,7 +1981,7 @@ public function getDateTimeZone() {
 	 * @return IDateTimeFormatter
 	 * @deprecated 20.0.0
 	 */
-	public function getDateTimeFormatter() {
+	public function getDateTimeFormatter(): IDateTimeFormatter {
 		return $this->get(IDateTimeFormatter::class);
 	}
 
@@ -1990,7 +1989,7 @@ public function getDateTimeFormatter() {
 	 * @return IMountProviderCollection
 	 * @deprecated 20.0.0
 	 */
-	public function getMountProviderCollection() {
+	public function getMountProviderCollection(): IMountProviderCollection {
 		return $this->get(IMountProviderCollection::class);
 	}
 
@@ -2000,7 +1999,7 @@ public function getMountProviderCollection() {
 	 * @return IniGetWrapper
 	 * @deprecated 20.0.0
 	 */
-	public function getIniWrapper() {
+	public function getIniWrapper(): IniGetWrapper {
 		return $this->get(IniGetWrapper::class);
 	}
 
@@ -2008,7 +2007,7 @@ public function getIniWrapper() {
 	 * @return \OCP\Command\IBus
 	 * @deprecated 20.0.0
 	 */
-	public function getCommandBus() {
+	public function getCommandBus(): IBus {
 		return $this->get(IBus::class);
 	}
 
@@ -2018,7 +2017,7 @@ public function getCommandBus() {
 	 * @return TrustedDomainHelper
 	 * @deprecated 20.0.0
 	 */
-	public function getTrustedDomainHelper() {
+	public function getTrustedDomainHelper(): TrustedDomainHelper {
 		return $this->get(TrustedDomainHelper::class);
 	}
 
@@ -2029,7 +2028,7 @@ public function getTrustedDomainHelper() {
 	 * @since 8.1.0
 	 * @deprecated 20.0.0
 	 */
-	public function getLockingProvider() {
+	public function getLockingProvider(): ILockingProvider {
 		return $this->get(ILockingProvider::class);
 	}
 
@@ -2037,7 +2036,7 @@ public function getLockingProvider() {
 	 * @return IMountManager
 	 * @deprecated 20.0.0
 	 **/
-	public function getMountManager() {
+	public function getMountManager(): IMountManager {
 		return $this->get(IMountManager::class);
 	}
 
@@ -2045,7 +2044,7 @@ public function getMountManager() {
 	 * @return IUserMountCache
 	 * @deprecated 20.0.0
 	 */
-	public function getUserMountCache() {
+	public function getUserMountCache(): IUserMountCache {
 		return $this->get(IUserMountCache::class);
 	}
 
@@ -2055,7 +2054,7 @@ public function getUserMountCache() {
 	 * @return IMimeTypeDetector
 	 * @deprecated 20.0.0
 	 */
-	public function getMimeTypeDetector() {
+	public function getMimeTypeDetector(): IMimeTypeDetector {
 		return $this->get(IMimeTypeDetector::class);
 	}
 
@@ -2065,7 +2064,7 @@ public function getMimeTypeDetector() {
 	 * @return IMimeTypeLoader
 	 * @deprecated 20.0.0
 	 */
-	public function getMimeTypeLoader() {
+	public function getMimeTypeLoader(): IMimeTypeLoader {
 		return $this->get(IMimeTypeLoader::class);
 	}
 
@@ -2075,7 +2074,7 @@ public function getMimeTypeLoader() {
 	 * @return CapabilitiesManager
 	 * @deprecated 20.0.0
 	 */
-	public function getCapabilitiesManager() {
+	public function getCapabilitiesManager(): CapabilitiesManager {
 		return $this->get(CapabilitiesManager::class);
 	}
 
@@ -2086,7 +2085,7 @@ public function getCapabilitiesManager() {
 	 * @since 8.2.0
 	 * @deprecated 20.0.0
 	 */
-	public function getNotificationManager() {
+	public function getNotificationManager(): \OCP\Notification\IManager {
 		return $this->get(\OCP\Notification\IManager::class);
 	}
 
@@ -2094,7 +2093,7 @@ public function getNotificationManager() {
 	 * @return ICommentsManager
 	 * @deprecated 20.0.0
 	 */
-	public function getCommentsManager() {
+	public function getCommentsManager(): ICommentsManager {
 		return $this->get(ICommentsManager::class);
 	}
 
@@ -2102,7 +2101,7 @@ public function getCommentsManager() {
 	 * @return \OCA\Theming\ThemingDefaults
 	 * @deprecated 20.0.0
 	 */
-	public function getThemingDefaults() {
+	public function getThemingDefaults(): ThemingDefaults {
 		return $this->get('ThemingDefaults');
 	}
 
@@ -2110,7 +2109,7 @@ public function getThemingDefaults() {
 	 * @return \OC\IntegrityCheck\Checker
 	 * @deprecated 20.0.0
 	 */
-	public function getIntegrityCodeChecker() {
+	public function getIntegrityCodeChecker(): Checker {
 		return $this->get('IntegrityCodeChecker');
 	}
 
@@ -2118,7 +2117,7 @@ public function getIntegrityCodeChecker() {
 	 * @return \OC\Session\CryptoWrapper
 	 * @deprecated 20.0.0
 	 */
-	public function getSessionCryptoWrapper() {
+	public function getSessionCryptoWrapper(): CryptoWrapper {
 		return $this->get('CryptoWrapper');
 	}
 
@@ -2126,7 +2125,7 @@ public function getSessionCryptoWrapper() {
 	 * @return CsrfTokenManager
 	 * @deprecated 20.0.0
 	 */
-	public function getCsrfTokenManager() {
+	public function getCsrfTokenManager(): CsrfTokenManager {
 		return $this->get(CsrfTokenManager::class);
 	}
 
@@ -2134,7 +2133,7 @@ public function getCsrfTokenManager() {
 	 * @return IThrottler
 	 * @deprecated 20.0.0
 	 */
-	public function getBruteForceThrottler() {
+	public function getBruteForceThrottler(): Throttler {
 		return $this->get(Throttler::class);
 	}
 
@@ -2142,7 +2141,7 @@ public function getBruteForceThrottler() {
 	 * @return IContentSecurityPolicyManager
 	 * @deprecated 20.0.0
 	 */
-	public function getContentSecurityPolicyManager() {
+	public function getContentSecurityPolicyManager(): IContentSecurityPolicyManager {
 		return $this->get(ContentSecurityPolicyManager::class);
 	}
 
@@ -2150,7 +2149,7 @@ public function getContentSecurityPolicyManager() {
 	 * @return ContentSecurityPolicyNonceManager
 	 * @deprecated 20.0.0
 	 */
-	public function getContentSecurityPolicyNonceManager() {
+	public function getContentSecurityPolicyNonceManager(): ContentSecurityPolicyNonceManager {
 		return $this->get(ContentSecurityPolicyNonceManager::class);
 	}
 
@@ -2160,7 +2159,7 @@ public function getContentSecurityPolicyNonceManager() {
 	 * @return \OCA\Files_External\Service\BackendService
 	 * @deprecated 20.0.0
 	 */
-	public function getStoragesBackendService() {
+	public function getStoragesBackendService(): BackendService {
 		return $this->get(BackendService::class);
 	}
 
@@ -2170,7 +2169,7 @@ public function getStoragesBackendService() {
 	 * @return \OCA\Files_External\Service\GlobalStoragesService
 	 * @deprecated 20.0.0
 	 */
-	public function getGlobalStoragesService() {
+	public function getGlobalStoragesService(): GlobalStoragesService {
 		return $this->get(GlobalStoragesService::class);
 	}
 
@@ -2180,7 +2179,7 @@ public function getGlobalStoragesService() {
 	 * @return \OCA\Files_External\Service\UserGlobalStoragesService
 	 * @deprecated 20.0.0
 	 */
-	public function getUserGlobalStoragesService() {
+	public function getUserGlobalStoragesService(): UserGlobalStoragesService {
 		return $this->get(UserGlobalStoragesService::class);
 	}
 
@@ -2190,7 +2189,7 @@ public function getUserGlobalStoragesService() {
 	 * @return \OCA\Files_External\Service\UserStoragesService
 	 * @deprecated 20.0.0
 	 */
-	public function getUserStoragesService() {
+	public function getUserStoragesService(): UserStoragesService {
 		return $this->get(UserStoragesService::class);
 	}
 
@@ -2198,7 +2197,7 @@ public function getUserStoragesService() {
 	 * @return \OCP\Share\IManager
 	 * @deprecated 20.0.0
 	 */
-	public function getShareManager() {
+	public function getShareManager(): \OCP\Share\IManager {
 		return $this->get(\OCP\Share\IManager::class);
 	}
 
@@ -2206,7 +2205,7 @@ public function getShareManager() {
 	 * @return \OCP\Collaboration\Collaborators\ISearch
 	 * @deprecated 20.0.0
 	 */
-	public function getCollaboratorSearch() {
+	public function getCollaboratorSearch(): \OCP\Collaboration\Collaborators\ISearch {
 		return $this->get(\OCP\Collaboration\Collaborators\ISearch::class);
 	}
 
@@ -2214,7 +2213,7 @@ public function getCollaboratorSearch() {
 	 * @return \OCP\Collaboration\AutoComplete\IManager
 	 * @deprecated 20.0.0
 	 */
-	public function getAutoCompleteManager() {
+	public function getAutoCompleteManager(): IManager {
 		return $this->get(IManager::class);
 	}
 
@@ -2224,7 +2223,7 @@ public function getAutoCompleteManager() {
 	 * @return \OCP\LDAP\ILDAPProvider
 	 * @deprecated 20.0.0
 	 */
-	public function getLDAPProvider() {
+	public function getLDAPProvider(): ILDAPProvider {
 		return $this->get('LDAPProvider');
 	}
 
@@ -2232,7 +2231,7 @@ public function getLDAPProvider() {
 	 * @return \OCP\Settings\IManager
 	 * @deprecated 20.0.0
 	 */
-	public function getSettingsManager() {
+	public function getSettingsManager(): \OCP\Settings\IManager {
 		return $this->get(\OC\Settings\Manager::class);
 	}
 
@@ -2240,7 +2239,7 @@ public function getSettingsManager() {
 	 * @return \OCP\Files\IAppData
 	 * @deprecated 20.0.0 Use get(\OCP\Files\AppData\IAppDataFactory::class)->get($app) instead
 	 */
-	public function getAppDataDir($app) {
+	public function getAppDataDir($app): \OCP\Files\IAppData {
 		/** @var \OC\Files\AppData\Factory $factory */
 		$factory = $this->get(\OC\Files\AppData\Factory::class);
 		return $factory->get($app);
@@ -2250,7 +2249,7 @@ public function getAppDataDir($app) {
 	 * @return \OCP\Lockdown\ILockdownManager
 	 * @deprecated 20.0.0
 	 */
-	public function getLockdownManager() {
+	public function getLockdownManager(): ILockdownManager {
 		return $this->get('LockdownManager');
 	}
 
@@ -2258,7 +2257,7 @@ public function getLockdownManager() {
 	 * @return \OCP\Federation\ICloudIdManager
 	 * @deprecated 20.0.0
 	 */
-	public function getCloudIdManager() {
+	public function getCloudIdManager(): ICloudIdManager {
 		return $this->get(ICloudIdManager::class);
 	}
 
@@ -2266,7 +2265,7 @@ public function getCloudIdManager() {
 	 * @return \OCP\GlobalScale\IConfig
 	 * @deprecated 20.0.0
 	 */
-	public function getGlobalScaleConfig() {
+	public function getGlobalScaleConfig(): IConfig {
 		return $this->get(IConfig::class);
 	}
 
@@ -2274,7 +2273,7 @@ public function getGlobalScaleConfig() {
 	 * @return \OCP\Federation\ICloudFederationProviderManager
 	 * @deprecated 20.0.0
 	 */
-	public function getCloudFederationProviderManager() {
+	public function getCloudFederationProviderManager(): ICloudFederationProviderManager {
 		return $this->get(ICloudFederationProviderManager::class);
 	}
 
@@ -2282,7 +2281,7 @@ public function getCloudFederationProviderManager() {
 	 * @return \OCP\Remote\Api\IApiFactory
 	 * @deprecated 20.0.0
 	 */
-	public function getRemoteApiFactory() {
+	public function getRemoteApiFactory(): IApiFactory {
 		return $this->get(IApiFactory::class);
 	}
 
@@ -2290,7 +2289,7 @@ public function getRemoteApiFactory() {
 	 * @return \OCP\Federation\ICloudFederationFactory
 	 * @deprecated 20.0.0
 	 */
-	public function getCloudFederationFactory() {
+	public function getCloudFederationFactory(): ICloudFederationFactory {
 		return $this->get(ICloudFederationFactory::class);
 	}
 
@@ -2298,7 +2297,7 @@ public function getCloudFederationFactory() {
 	 * @return \OCP\Remote\IInstanceFactory
 	 * @deprecated 20.0.0
 	 */
-	public function getRemoteInstanceFactory() {
+	public function getRemoteInstanceFactory(): IInstanceFactory {
 		return $this->get(IInstanceFactory::class);
 	}
 
@@ -2306,7 +2305,7 @@ public function getRemoteInstanceFactory() {
 	 * @return IStorageFactory
 	 * @deprecated 20.0.0
 	 */
-	public function getStorageFactory() {
+	public function getStorageFactory(): IStorageFactory {
 		return $this->get(IStorageFactory::class);
 	}
 
@@ -2317,11 +2316,11 @@ public function getStorageFactory() {
 	 * @since 17.0.0
 	 * @deprecated 20.0.0
 	 */
-	public function getGeneratorHelper() {
+	public function getGeneratorHelper(): GeneratorHelper {
 		return $this->get(\OC\Preview\GeneratorHelper::class);
 	}
 
-	private function registerDeprecatedAlias(string $alias, string $target) {
+	private function registerDeprecatedAlias(string $alias, string $target): void {
 		$this->registerService($alias, function (ContainerInterface $container) use ($target, $alias) {
 			try {
 				/** @var LoggerInterface $logger */
diff --git a/lib/private/ServerContainer.php b/lib/private/ServerContainer.php
index daa480a75d11d..67a254883bffc 100644
--- a/lib/private/ServerContainer.php
+++ b/lib/private/ServerContainer.php
@@ -40,13 +40,13 @@
  */
 class ServerContainer extends SimpleContainer {
 	/** @var DIContainer[] */
-	protected $appContainers;
+	protected array $appContainers;
 
 	/** @var string[] */
-	protected $hasNoAppContainer;
+	protected array $hasNoAppContainer;
 
 	/** @var string[] */
-	protected $namespaces;
+	protected array $namespaces;
 
 	/**
 	 * ServerContainer constructor.