diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index 08aa20e37..3d5a29c06 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        php-versions: [8.2]
+        php-versions: [8.3]
         nextcloud-versions: ['stable32', 'master']
         include:
             - php: 8.2
diff --git a/composer.json b/composer.json
index e479b701a..9b012e3a4 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,7 @@
     "require-dev": {
         "phpunit/phpunit": "^9.5",
         "nextcloud/coding-standard": "^1.1",
-        "nextcloud/ocp": "^30.0",
+        "nextcloud/ocp": "> 30.0 < 33.0",
         "symfony/console": "^6.3",
         "mockery/mockery": "^1.6",
         "nextcloud/openapi-extractor": "^1.0"
diff --git a/composer.lock b/composer.lock
index cea32ca93..cbedaca7a 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "c582bfdee5f081d8f02d004beead9d0b",
+    "content-hash": "f65c97f4b302e12d0a7e707880b9d078",
     "packages": [],
     "packages-dev": [
         {
@@ -203,16 +203,16 @@
         },
         {
             "name": "kubawerlos/php-cs-fixer-custom-fixers",
-            "version": "v3.36.0",
+            "version": "v3.37.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/kubawerlos/php-cs-fixer-custom-fixers.git",
-                "reference": "e1f97f6463f0b2a22e0dd320948a04132ff9c501"
+                "reference": "c31fb2aa359dcb25fb48cc6f600810ad284343be"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/kubawerlos/php-cs-fixer-custom-fixers/zipball/e1f97f6463f0b2a22e0dd320948a04132ff9c501",
-                "reference": "e1f97f6463f0b2a22e0dd320948a04132ff9c501",
+                "url": "https://api.github.com/repos/kubawerlos/php-cs-fixer-custom-fixers/zipball/c31fb2aa359dcb25fb48cc6f600810ad284343be",
+                "reference": "c31fb2aa359dcb25fb48cc6f600810ad284343be",
                 "shasum": ""
             },
             "require": {
@@ -243,7 +243,7 @@
             "description": "A set of custom fixers for PHP CS Fixer",
             "support": {
                 "issues": "https://github.com/kubawerlos/php-cs-fixer-custom-fixers/issues",
-                "source": "https://github.com/kubawerlos/php-cs-fixer-custom-fixers/tree/v3.36.0"
+                "source": "https://github.com/kubawerlos/php-cs-fixer-custom-fixers/tree/v3.37.0"
             },
             "funding": [
                 {
@@ -251,7 +251,7 @@
                     "type": "github"
                 }
             ],
-            "time": "2026-01-31T07:02:11+00:00"
+            "time": "2026-04-16T16:49:13+00:00"
         },
         {
             "name": "mockery/mockery",
@@ -443,29 +443,29 @@
         },
         {
             "name": "nextcloud/ocp",
-            "version": "v30.0.9",
+            "version": "v32.0.8",
             "source": {
                 "type": "git",
                 "url": "https://github.com/nextcloud-deps/ocp.git",
-                "reference": "d6000d61d8ae708199bd90e1da0c794712c81030"
+                "reference": "9eff94dcc966d95c1f1621cad35f0d83160b42eb"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/nextcloud-deps/ocp/zipball/d6000d61d8ae708199bd90e1da0c794712c81030",
-                "reference": "d6000d61d8ae708199bd90e1da0c794712c81030",
+                "url": "https://api.github.com/repos/nextcloud-deps/ocp/zipball/9eff94dcc966d95c1f1621cad35f0d83160b42eb",
+                "reference": "9eff94dcc966d95c1f1621cad35f0d83160b42eb",
                 "shasum": ""
             },
             "require": {
-                "php": "~8.0 || ~8.1 || ~8.2 || ~8.3",
+                "php": "~8.1 || ~8.2 || ~8.3 || ~8.4",
                 "psr/clock": "^1.0",
                 "psr/container": "^2.0.2",
                 "psr/event-dispatcher": "^1.0",
-                "psr/log": "^2.0.0"
+                "psr/log": "^3.0.2"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-stable30": "30.0.0-dev"
+                    "dev-stable32": "32.0.0-dev"
                 }
             },
             "notification-url": "https://packagist.org/downloads/",
@@ -476,14 +476,18 @@
                 {
                     "name": "Christoph Wurst",
                     "email": "christoph@winzerhof-wurst.at"
+                },
+                {
+                    "name": "Joas Schilling",
+                    "email": "coding@schilljs.com"
                 }
             ],
-            "description": "Composer package containing Nextcloud's public API (classes, interfaces)",
+            "description": "Composer package containing Nextcloud's public OCP API and the unstable NCU API",
             "support": {
                 "issues": "https://github.com/nextcloud-deps/ocp/issues",
-                "source": "https://github.com/nextcloud-deps/ocp/tree/v30.0.9"
+                "source": "https://github.com/nextcloud-deps/ocp/tree/v32.0.8"
             },
-            "time": "2025-03-31T13:55:31+00:00"
+            "time": "2026-03-27T01:17:35+00:00"
         },
         {
             "name": "nextcloud/openapi-extractor",
@@ -710,16 +714,16 @@
         },
         {
             "name": "php-cs-fixer/shim",
-            "version": "v3.94.2",
+            "version": "v3.95.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/PHP-CS-Fixer/shim.git",
-                "reference": "80fd29f44a736136a2f05bae5464816a444b91d1"
+                "reference": "f81ccf51ca60cc9dd21358ffba0e79ebd2ebb78a"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/PHP-CS-Fixer/shim/zipball/80fd29f44a736136a2f05bae5464816a444b91d1",
-                "reference": "80fd29f44a736136a2f05bae5464816a444b91d1",
+                "url": "https://api.github.com/repos/PHP-CS-Fixer/shim/zipball/f81ccf51ca60cc9dd21358ffba0e79ebd2ebb78a",
+                "reference": "f81ccf51ca60cc9dd21358ffba0e79ebd2ebb78a",
                 "shasum": ""
             },
             "require": {
@@ -756,9 +760,9 @@
             "description": "A tool to automatically fix PHP code style",
             "support": {
                 "issues": "https://github.com/PHP-CS-Fixer/shim/issues",
-                "source": "https://github.com/PHP-CS-Fixer/shim/tree/v3.94.2"
+                "source": "https://github.com/PHP-CS-Fixer/shim/tree/v3.95.1"
             },
-            "time": "2026-02-20T16:14:17+00:00"
+            "time": "2026-04-12T17:00:34+00:00"
         },
         {
             "name": "phpstan/phpdoc-parser",
@@ -1390,16 +1394,16 @@
         },
         {
             "name": "psr/log",
-            "version": "2.0.0",
+            "version": "3.0.2",
             "source": {
                 "type": "git",
                 "url": "https://github.com/php-fig/log.git",
-                "reference": "ef29f6d262798707a9edd554e2b82517ef3a9376"
+                "reference": "f16e1d5863e37f8d8c2a01719f5b34baa2b714d3"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/php-fig/log/zipball/ef29f6d262798707a9edd554e2b82517ef3a9376",
-                "reference": "ef29f6d262798707a9edd554e2b82517ef3a9376",
+                "url": "https://api.github.com/repos/php-fig/log/zipball/f16e1d5863e37f8d8c2a01719f5b34baa2b714d3",
+                "reference": "f16e1d5863e37f8d8c2a01719f5b34baa2b714d3",
                 "shasum": ""
             },
             "require": {
@@ -1408,7 +1412,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "2.0.x-dev"
+                    "dev-master": "3.x-dev"
                 }
             },
             "autoload": {
@@ -1434,9 +1438,9 @@
                 "psr-3"
             ],
             "support": {
-                "source": "https://github.com/php-fig/log/tree/2.0.0"
+                "source": "https://github.com/php-fig/log/tree/3.0.2"
             },
-            "time": "2021-07-14T16:41:46+00:00"
+            "time": "2024-09-11T13:17:53+00:00"
         },
         {
             "name": "sebastian/cli-parser",
@@ -2451,16 +2455,16 @@
         },
         {
             "name": "symfony/console",
-            "version": "v6.4.34",
+            "version": "v6.4.36",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/console.git",
-                "reference": "7b1f1c37eff5910ddda2831345467e593a5120ad"
+                "reference": "9f481cfb580db8bcecc9b2d4c63f3e13df022ad5"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/console/zipball/7b1f1c37eff5910ddda2831345467e593a5120ad",
-                "reference": "7b1f1c37eff5910ddda2831345467e593a5120ad",
+                "url": "https://api.github.com/repos/symfony/console/zipball/9f481cfb580db8bcecc9b2d4c63f3e13df022ad5",
+                "reference": "9f481cfb580db8bcecc9b2d4c63f3e13df022ad5",
                 "shasum": ""
             },
             "require": {
@@ -2525,7 +2529,7 @@
                 "terminal"
             ],
             "support": {
-                "source": "https://github.com/symfony/console/tree/v6.4.34"
+                "source": "https://github.com/symfony/console/tree/v6.4.36"
             },
             "funding": [
                 {
@@ -2545,7 +2549,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2026-02-23T15:42:15+00:00"
+            "time": "2026-03-27T15:30:51+00:00"
         },
         {
             "name": "symfony/deprecation-contracts",
@@ -2616,16 +2620,16 @@
         },
         {
             "name": "symfony/polyfill-ctype",
-            "version": "v1.33.0",
+            "version": "v1.36.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/polyfill-ctype.git",
-                "reference": "a3cc8b044a6ea513310cbd48ef7333b384945638"
+                "reference": "141046a8f9477948ff284fa65be2095baafb94f2"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/polyfill-ctype/zipball/a3cc8b044a6ea513310cbd48ef7333b384945638",
-                "reference": "a3cc8b044a6ea513310cbd48ef7333b384945638",
+                "url": "https://api.github.com/repos/symfony/polyfill-ctype/zipball/141046a8f9477948ff284fa65be2095baafb94f2",
+                "reference": "141046a8f9477948ff284fa65be2095baafb94f2",
                 "shasum": ""
             },
             "require": {
@@ -2675,7 +2679,7 @@
                 "portable"
             ],
             "support": {
-                "source": "https://github.com/symfony/polyfill-ctype/tree/v1.33.0"
+                "source": "https://github.com/symfony/polyfill-ctype/tree/v1.36.0"
             },
             "funding": [
                 {
@@ -2695,20 +2699,20 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2024-09-09T11:45:10+00:00"
+            "time": "2026-04-10T16:19:22+00:00"
         },
         {
             "name": "symfony/polyfill-intl-grapheme",
-            "version": "v1.33.0",
+            "version": "v1.36.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/polyfill-intl-grapheme.git",
-                "reference": "380872130d3a5dd3ace2f4010d95125fde5d5c70"
+                "reference": "ad1b7b9092976d6c948b8a187cec9faaea9ec1df"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/polyfill-intl-grapheme/zipball/380872130d3a5dd3ace2f4010d95125fde5d5c70",
-                "reference": "380872130d3a5dd3ace2f4010d95125fde5d5c70",
+                "url": "https://api.github.com/repos/symfony/polyfill-intl-grapheme/zipball/ad1b7b9092976d6c948b8a187cec9faaea9ec1df",
+                "reference": "ad1b7b9092976d6c948b8a187cec9faaea9ec1df",
                 "shasum": ""
             },
             "require": {
@@ -2757,7 +2761,7 @@
                 "shim"
             ],
             "support": {
-                "source": "https://github.com/symfony/polyfill-intl-grapheme/tree/v1.33.0"
+                "source": "https://github.com/symfony/polyfill-intl-grapheme/tree/v1.36.0"
             },
             "funding": [
                 {
@@ -2777,11 +2781,11 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2025-06-27T09:58:17+00:00"
+            "time": "2026-04-10T16:19:22+00:00"
         },
         {
             "name": "symfony/polyfill-intl-normalizer",
-            "version": "v1.33.0",
+            "version": "v1.36.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/polyfill-intl-normalizer.git",
@@ -2842,7 +2846,7 @@
                 "shim"
             ],
             "support": {
-                "source": "https://github.com/symfony/polyfill-intl-normalizer/tree/v1.33.0"
+                "source": "https://github.com/symfony/polyfill-intl-normalizer/tree/v1.36.0"
             },
             "funding": [
                 {
@@ -2866,16 +2870,16 @@
         },
         {
             "name": "symfony/polyfill-mbstring",
-            "version": "v1.33.0",
+            "version": "v1.36.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/polyfill-mbstring.git",
-                "reference": "6d857f4d76bd4b343eac26d6b539585d2bc56493"
+                "reference": "6a21eb99c6973357967f6ce3708cd55a6bec6315"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/polyfill-mbstring/zipball/6d857f4d76bd4b343eac26d6b539585d2bc56493",
-                "reference": "6d857f4d76bd4b343eac26d6b539585d2bc56493",
+                "url": "https://api.github.com/repos/symfony/polyfill-mbstring/zipball/6a21eb99c6973357967f6ce3708cd55a6bec6315",
+                "reference": "6a21eb99c6973357967f6ce3708cd55a6bec6315",
                 "shasum": ""
             },
             "require": {
@@ -2927,7 +2931,7 @@
                 "shim"
             ],
             "support": {
-                "source": "https://github.com/symfony/polyfill-mbstring/tree/v1.33.0"
+                "source": "https://github.com/symfony/polyfill-mbstring/tree/v1.36.0"
             },
             "funding": [
                 {
@@ -2947,7 +2951,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2024-12-23T08:48:59+00:00"
+            "time": "2026-04-10T17:25:58+00:00"
         },
         {
             "name": "symfony/service-contracts",
@@ -3038,16 +3042,16 @@
         },
         {
             "name": "symfony/string",
-            "version": "v7.4.6",
+            "version": "v7.4.8",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/string.git",
-                "reference": "9f209231affa85aa930a5e46e6eb03381424b30b"
+                "reference": "114ac57257d75df748eda23dd003878080b8e688"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/string/zipball/9f209231affa85aa930a5e46e6eb03381424b30b",
-                "reference": "9f209231affa85aa930a5e46e6eb03381424b30b",
+                "url": "https://api.github.com/repos/symfony/string/zipball/114ac57257d75df748eda23dd003878080b8e688",
+                "reference": "114ac57257d75df748eda23dd003878080b8e688",
                 "shasum": ""
             },
             "require": {
@@ -3105,7 +3109,7 @@
                 "utf8"
             ],
             "support": {
-                "source": "https://github.com/symfony/string/tree/v7.4.6"
+                "source": "https://github.com/symfony/string/tree/v7.4.8"
             },
             "funding": [
                 {
@@ -3125,7 +3129,7 @@
                     "type": "tidelift"
                 }
             ],
-            "time": "2026-02-09T09:33:46+00:00"
+            "time": "2026-03-24T13:12:05+00:00"
         },
         {
             "name": "theseer/tokenizer",
diff --git a/lib/AppInfo/Application.php b/lib/AppInfo/Application.php
index 89564152e..3f8bd6f64 100644
--- a/lib/AppInfo/Application.php
+++ b/lib/AppInfo/Application.php
@@ -39,6 +39,7 @@
 use OCA\Workspace\Middleware\WorkspaceManagerAccessMiddleware;
 use OCA\Workspace\Service\SpaceService;
 use OCA\Workspace\Service\UserService;
+use OCA\Workspace\User\Backend\UserBackend;
 use OCP\AppFramework\App;
 use OCP\AppFramework\Bootstrap\IBootContext;
 use OCP\AppFramework\Bootstrap\IBootstrap;
@@ -47,6 +48,7 @@
 use OCP\AppFramework\Utility\IControllerMethodReflector;
 use OCP\IGroupManager;
 use OCP\IRequest;
+use OCP\IUserManager;
 
 class Application extends App implements IBootstrap {
 	public const APP_ID = 'workspace';
@@ -98,6 +100,10 @@ public function register(IRegistrationContext $context): void {
 			$groupBackend = $container->get(GroupBackend::class);
 			$groupManager->addBackend($groupBackend);
 		}
+
+		$userManager = $container->get(IUserManager::class);
+		$userBackend = $container->get(UserBackend::class);
+		$userManager->registerBackend($userBackend);
 	}
 
 	public function boot(IBootContext $context): void {
diff --git a/lib/Group/GroupBackend.php b/lib/Group/GroupBackend.php
index 9ee1e763a..2b92010f8 100644
--- a/lib/Group/GroupBackend.php
+++ b/lib/Group/GroupBackend.php
@@ -82,11 +82,21 @@ public function getUserGroups($uid) {
 		} else {
 			$groupIds = [];
 		}
+
+		$userGroups = [];
+		if (str_starts_with($uid, 'SPACE-UWS-')) {
+			$spaceId = (int)substr($uid, 10);
+			if ($spaceId !== 0) {
+				$userGroups[] = "SPACE-U-{$spaceId}";
+				/// @TODO is it necessary ?
+				// $groupIds[] = "SPACE-GE-{$spaceId}";
+			}
+		}
+
 		$this->avoidRecurse_groups = $avoid;
 		if (empty($groupIds)) {
-			return [];
+			return $userGroups;
 		}
-		$userGroups = [];
 		foreach ($groupIds as $gid) {
 			$connectedGids = $this->connectedGroups->getConnectedSpaceToGroupIds($gid);
 			if ($connectedGids !== null && $user->isEnabled()) {
@@ -118,6 +128,9 @@ public function getGroups($search = '', $limit = -1, $offset = 0) {
 	 */
 	public function groupExists($gid) {
 		// @note : need to implement, but this backend doesn't manage existence of connected groups
+		if (str_starts_with($gid, 'SPACE-U-') && !$this->avoidRecurse_groups) {
+			return true;
+		}
 		return $this->connectedGroups->hasConnectedGroups($gid);
 	}
 
@@ -134,12 +147,19 @@ public function usersInGroup($gid, $search = '', $limit = -1, $offset = 0) {
 			return [];
 		}
 
+		$users = [];
+		if (str_starts_with($gid, 'SPACE-U-')) {
+			$spaceId = (int)substr($gid, 8);
+			if ($spaceId !== 0) {
+				$users[] = "SPACE-UWS-{$spaceId}";
+			}
+		}
+
 		$groups = $this->connectedGroups->getConnectedGroupsToSpaceGroup($gid);
 		if ($groups === null) {
-			return [];
+			return $users;
 		}
 
-		$users = [];
 		$avoid = $this->avoidRecurse_users;
 		$this->avoidRecurse_users = true;
 		foreach ($groups as $group) {
@@ -152,6 +172,7 @@ public function usersInGroup($gid, $search = '', $limit = -1, $offset = 0) {
 			}
 		}
 		$this->avoidRecurse_users = $avoid;
+
 		return $users;
 	}
 
@@ -182,4 +203,12 @@ public function countUsersInGroup(string $gid, string $search = ''): int {
 		}
 		return $nbUsers;
 	}
+
+	public function disable() {
+		$this->avoidRecurse_users = $this->avoidRecurse_groups = true;
+	}
+
+	public function enable() {
+		$this->avoidRecurse_users = $this->avoidRecurse_groups = false;
+	}
 };
diff --git a/lib/Service/Group/UserGroup.php b/lib/Service/Group/UserGroup.php
index 3676b48b6..90b0f7668 100644
--- a/lib/Service/Group/UserGroup.php
+++ b/lib/Service/Group/UserGroup.php
@@ -26,17 +26,20 @@
 
 use OCA\Workspace\Db\Space;
 use OCA\Workspace\Exceptions\CreateGroupException;
+use OCA\Workspace\Group\GroupBackend;
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Services\IAppConfig;
 use OCP\IGroup;
 use OCP\IGroupManager;
+use OCP\Server;
 
 class UserGroup extends GroupsWorkspace {
-	private IGroupManager $groupManager;
 
-	public function __construct(IGroupManager $groupManager, IAppConfig $appConfig) {
+	public function __construct(
+		IAppConfig $appConfig,
+		private IGroupManager $groupManager,
+	) {
 		parent::__construct($appConfig);
-		$this->groupManager = $groupManager;
 	}
 
 	public static function get(int $spaceId): string {
@@ -48,7 +51,10 @@ public static function getPrefix(): string {
 	}
 
 	public function create(Space $space): IGroup {
+		$groupBackend = Server::get(GroupBackend::class);
+		$groupBackend->disable();
 		$group = $this->groupManager->createGroup(self::PREFIX_GID_USERS . $space->getId());
+		$groupBackend->enable();
 
 		if (is_null($group)) {
 			throw new CreateGroupException('Error to create a Space Manager group.', Http::STATUS_CONFLICT);
diff --git a/lib/User/Backend/UserBackend.php b/lib/User/Backend/UserBackend.php
new file mode 100644
index 000000000..04cf7d313
--- /dev/null
+++ b/lib/User/Backend/UserBackend.php
@@ -0,0 +1,245 @@
+<?php
+
+namespace OCA\Workspace\User\Backend;
+
+use OC\User\Backend;
+use OC\User\NoUserException;
+use OCA\Workspace\Db\SpaceMapper;
+use OCP\IUserBackend;
+use OCP\Notification\IManager as INotificationManager;
+use OCP\User\Backend\ILimitAwareCountUsersBackend;
+use OCP\User\Backend\IProvideEnabledStateBackend;
+use OCP\UserInterface;
+use Psr\Log\LoggerInterface;
+
+class UserBackend implements IUserBackend, UserInterface, ILimitAwareCountUsersBackend, IProvideEnabledStateBackend {
+
+	/** @var array<string,string> */
+	private $_users = null;
+
+	public function __construct(
+		protected INotificationManager $notificationManager,
+		protected LoggerInterface $logger,
+		private SpaceMapper $spaceMapper,
+	) {
+	}
+
+	private function initUsers(): void {
+		if ($this->_users !== null) {
+			return;
+		}
+
+		$users = [];
+		$spaces = $this->spaceMapper->findAll();
+		/** @var Space $space */
+		foreach ($spaces as $space) {
+			$users['SPACE-UWS-' . $space->getSpaceId()] = [
+				'displayName' => $space->getSpaceName(),
+			];
+		}
+		$this->_users = $users;
+	}
+
+	/**
+	 * checks whether the user is allowed to change their avatar in Nextcloud
+	 *
+	 * @param string $uid the Nextcloud user name
+	 * @return boolean either the user can or cannot
+	 * @throws \Exception
+	 */
+	public function canChangeAvatar($uid) {
+		return false;
+	}
+
+	/**
+	 * Get a list of all users
+	 *
+	 * @param string $search
+	 * @param integer $limit
+	 * @param integer $offset
+	 * @return string[] an array of all uids
+	 */
+	public function getUsers($search = '', $limit = 10, $offset = 0) {
+		$this->initUsers();
+		$limit = (is_int($limit) && $limit >= 0) ? $limit : null;
+		if ($limit === null && $offset === 0 && $search === '') {
+			return array_keys($this->_users);
+		}
+		if ($search === '') {
+			return array_slice(array_keys($this->_users), $offset, $limit);
+		}
+		$search = strtolower($search);
+		$users = [];
+		$count = 0;
+		foreach ($this->_users as $uid => $user) {
+			if (str_contains(strtolower($user['displayName']), $search)) {
+				if ($count >= $offset) {
+					$users[] = $uid;
+				}
+				$count++;
+				if ($limit !== null && $count >= $offset + $limit) {
+					break;
+				}
+			}
+		}
+		return $users;
+	}
+
+	/**
+	 * check if a user exists
+	 * @param string $uid the username
+	 * @return boolean
+	 * @throws \Exception when connection could not be established
+	 */
+	public function userExists($uid) {
+		$this->initUsers();
+		return array_key_exists($uid, $this->_users);
+	}
+
+	/**
+	 * returns whether a user was deleted in LDAP
+	 *
+	 * @param string $uid The username of the user to delete
+	 * @return bool
+	 */
+	public function deleteUser($uid) {
+		return false;
+	}
+
+	/**
+	 * get the user's home directory
+	 *
+	 * @param string $uid the username
+	 * @return bool|string
+	 * @throws NoUserException
+	 * @throws \Exception
+	 */
+	public function getHome($uid) {
+		return false;
+	}
+
+	/**
+	 * get display name of the user
+	 * @param string $uid user ID of the user
+	 * @return string|false display name
+	 */
+	public function getDisplayName($uid) {
+		$this->initUsers();
+		if (isset($this->_users[$uid]) && isset($this->_users[$uid]['displayName'])) {
+			return $this->_users[$uid]['displayName'];
+		}
+		return false;
+	}
+
+	/**
+	 * set display name of the user
+	 * @param string $uid user ID of the user
+	 * @param string $displayName new display name of the user
+	 * @return string|false display name
+	 */
+	public function setDisplayName($uid, $displayName) {
+		return false;
+	}
+
+	/**
+	 * Get a list of all display names
+	 *
+	 * @param string $search
+	 * @param int|null $limit
+	 * @param int|null $offset
+	 * @return array an array of all displayNames (value) and the corresponding uids (key)
+	 */
+	public function getDisplayNames($search = '', $limit = null, $offset = null) {
+		$this->initUsers();
+		return array_combine(
+			array_keys($this->_users),
+			array_column($this->_users, 'displayName')
+		);
+	}
+
+	/**
+	 * Check if backend implements actions
+	 * @param int $actions bitwise-or'ed actions
+	 * @return boolean
+	 *
+	 * Returns the supported actions as int to be
+	 * compared with \OC\User\Backend::CREATE_USER etc.
+	 */
+	public function implementsActions($actions) {
+		return (bool)(
+			// Backend::CHECK_PASSWORD
+			// | Backend::GET_HOME
+			(Backend::GET_DISPLAYNAME
+			// | (($this->access->connection->ldapUserAvatarRule !== 'none') ? Backend::PROVIDE_AVATAR : 0)
+			| Backend::COUNT_USERS)
+			// | (((int)$this->access->connection->turnOnPasswordChange === 1)? Backend::SET_PASSWORD :0)
+			// | $this->userPluginManager->getImplementedActions())
+			& $actions);
+	}
+
+	/**
+	 * @return bool
+	 */
+	public function hasUserListings() {
+		return true;
+	}
+
+	/**
+	 * counts the users in LDAP
+	 */
+	public function countUsers(int $limit = 0): int|false {
+		$this->initUsers();
+		return count($this->_users);
+	}
+
+
+	/**
+	 * Backend name to be shown in user management
+	 * @return string the name of the backend to be shown
+	 */
+	public function getBackendName() {
+		return 'WorkSpace';
+	}
+
+	/**
+	 * @since 28.0.0
+	 *
+	 * @param callable():bool $queryDatabaseValue A callable to query the enabled state from database
+	 */
+	public function isUserEnabled(string $uid, callable $queryDatabaseValue): bool {
+		if (str_starts_with($uid, 'SPACE-UWS-')) {
+			$spaceId = (int)substr($uid, 10);
+			if ($spaceId !== 0) {
+				$space = $this->spaceMapper->find($spaceId);
+				return $space !== null;
+			}
+			return false;
+		}
+		return true;
+	}
+
+	/**
+	 * @since 28.0.0
+	 *
+	 * @param callable():bool $queryDatabaseValue A callable to query the enabled state from database
+	 * @param callable(bool):void $setDatabaseValue A callable to set the enabled state in the database.
+	 */
+	public function setUserEnabled(string $uid, bool $enabled, callable $queryDatabaseValue, callable $setDatabaseValue): bool {
+		if (str_starts_with($uid, 'SPACE-UWS-')) {
+			return !$enabled; // refuse change
+		}
+		return true;
+	}
+
+	/**
+	 * Get the list of disabled users, to merge with the ones disabled in database
+	 *
+	 * @since 28.0.0
+	 * @since 30.0.0 $search parameter added
+	 *
+	 * @return string[]
+	 */
+	public function getDisabledUserList(?int $limit = null, int $offset = 0, string $search = ''): array {
+		return [];
+	}
+}