diff --git a/appinfo/info.xml b/appinfo/info.xml
index 85de603..2a79e40 100644
--- a/appinfo/info.xml
+++ b/appinfo/info.xml
@@ -21,8 +21,8 @@
     </types>
     <category>auth</category>
     <dependencies>
-        <php min-version="8.0"/>
-        <nextcloud min-version="31" max-version="31"/>
+        <php min-version="8.4"/>
+        <nextcloud min-version="31" max-version="33"/>
     </dependencies>
     <settings>
         <admin>\OCA\UserSQL\Settings\Admin</admin>
diff --git a/appinfo/routes.php b/appinfo/routes.php
index dde5395..46429a6 100644
--- a/appinfo/routes.php
+++ b/appinfo/routes.php
@@ -2,8 +2,9 @@
 /**
  * Nextcloud - user_sql
  *
- * @copyright 2012-2015 Andreas Böhler <dev (at) aboehler (dot) at>
+ * @copyright 2025 Claus-Justus Heine <himself@claus-justus-heine.de>
  * @copyright 2018 Marcin Łojewski <dev@mlojewski.me>
+ * @copyright 2012-2015 Andreas Böhler <dev (at) aboehler (dot) at>
  * @author    Marcin Łojewski <dev@mlojewski.me>
  *
  * This program is free software: you can redistribute it and/or modify
@@ -22,50 +23,49 @@
 
 use OCA\UserSQL\AppInfo\Application;
 
-$application = new Application();
-$application->registerRoutes(
-    $this, [
-        "routes" => [
-            [
-                "name" => "settings#verifyDbConnection",
-                "url" => "/settings/db/verify",
-                "verb" => "POST"
-            ],
-            [
-                "name" => "settings#saveProperties",
-                "url" => "/settings/properties",
-                "verb" => "POST"
-            ],
-            [
-                "name" => "settings#clearCache",
-                "url" => "/settings/cache/clear",
-                "verb" => "POST"
-            ],
-            [
-                "name" => "settings#tableAutocomplete",
-                "url" => "/settings/autocomplete/table",
-                "verb" => "POST"
-            ],
-            [
-                "name" => "settings#userTableAutocomplete",
-                "url" => "/settings/autocomplete/table/user",
-                "verb" => "POST"
-            ],
-            [
-                "name" => "settings#userGroupTableAutocomplete",
-                "url" => "/settings/autocomplete/table/user_group",
-                "verb" => "POST"
-            ],
-            [
-                "name" => "settings#groupTableAutocomplete",
-                "url" => "/settings/autocomplete/table/group",
-                "verb" => "POST"
-            ],
-            [
-                "name" => "settings#cryptoParams",
-                "url" => "/settings/crypto/params",
-                "verb" => "GET"
-            ],
-        ]
-    ]
-);
+$routes = [
+	'routes' => [
+		[
+			"name" => "settings#verifyDbConnection",
+			"url" => "/settings/db/verify",
+			"verb" => "POST"
+		],
+		[
+			"name" => "settings#saveProperties",
+			"url" => "/settings/properties",
+			"verb" => "POST"
+		],
+		[
+			"name" => "settings#clearCache",
+			"url" => "/settings/cache/clear",
+			"verb" => "POST"
+		],
+		[
+			"name" => "settings#tableAutocomplete",
+			"url" => "/settings/autocomplete/table",
+			"verb" => "POST"
+		],
+		[
+			"name" => "settings#userTableAutocomplete",
+			"url" => "/settings/autocomplete/table/user",
+			"verb" => "POST"
+		],
+		[
+			"name" => "settings#userGroupTableAutocomplete",
+			"url" => "/settings/autocomplete/table/user_group",
+			"verb" => "POST"
+		],
+		[
+			"name" => "settings#groupTableAutocomplete",
+			"url" => "/settings/autocomplete/table/group",
+			"verb" => "POST"
+		],
+		[
+			"name" => "settings#cryptoParams",
+			"url" => "/settings/crypto/params",
+			"verb" => "GET"
+		],
+	],
+];
+
+return $routes;
diff --git a/lib/AppInfo/Application.php b/lib/AppInfo/Application.php
index c16d2e8..578a24a 100644
--- a/lib/AppInfo/Application.php
+++ b/lib/AppInfo/Application.php
@@ -2,10 +2,10 @@
 /**
  * Nextcloud - user_sql
  *
- * @copyright 2018 Marcin Łojewski <dev@mlojewski.me>
- * @author    Marcin Łojewski <dev@mlojewski.me>
  * @copyright 2025 Claus-Justus Heine <himself@claus-justus-heine.de>
  * @author    Claus-Justus Heine <himself@claus-justus-heine.de>
+ * @copyright 2018 Marcin Łojewski <dev@mlojewski.me>
+ * @author    Marcin Łojewski <dev@mlojewski.me>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as
@@ -63,8 +63,12 @@ public function boot(IBootContext $context): void
 			IGroupManager $groupManager,
 			Backend\GroupBackend $groupBackend,
 		) {
-			$userManager->registerBackend($userBackend);
-			$groupManager->addBackend($groupBackend);
+			if ($userBackend->isConfigured()) {
+				$userManager->registerBackend($userBackend);
+			}
+			if ($groupBackend->isConfigured()) {
+				$groupManager->addBackend($groupBackend);
+			}
 		});
 	}
 }
diff --git a/lib/Backend/UserBackend.php b/lib/Backend/UserBackend.php
index 370d45d..842c1bc 100644
--- a/lib/Backend/UserBackend.php
+++ b/lib/Backend/UserBackend.php
@@ -261,13 +261,13 @@ private function getUser($uid)
         if ($user instanceof User) {
             $this->cache->set($cacheKey, $user);
 
-			// avoid recursion as the action may very well call into the UserManager again ...
-			$actions = $this->actions;
-			$this->actions = [];
-            foreach ($this->actions as $action) {
+            // avoid recursion as the action may very well call into the UserManager again ...
+            $actions = $this->actions;
+            $this->actions = [];
+            foreach ($actions as $action) {
                 $action->doAction($user);
             }
-			$this->actions = $actions;
+            $this->actions = $actions;
         }
 
         return $user;
diff --git a/lib/Query/DataQuery.php b/lib/Query/DataQuery.php
index ea33803..4203182 100644
--- a/lib/Query/DataQuery.php
+++ b/lib/Query/DataQuery.php
@@ -4,6 +4,8 @@
  *
  * @copyright 2021 Marcin Łojewski <dev@mlojewski.me>
  * @author    Marcin Łojewski <dev@mlojewski.me>
+ * @copyright 2025 Claus-Justus Heine
+ * @author    Claus-Justus Heine <himself@claus-justus-heine.de>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as
@@ -21,6 +23,8 @@
 
 namespace OCA\UserSQL\Query;
 
+use UnexpectedValueException;
+
 use Doctrine\DBAL\Driver\Statement;
 use Doctrine\DBAL\Exception as DBALException;
 use OC\DB\Connection;
@@ -151,6 +155,10 @@ private function connectToDatabase()
             "driverOptions" => array()
         );
 
+        if (empty($this->properties[DB::DRIVER])) {
+          throw new UnexpectedValueException('Attempt to connect without configuration.');
+        }
+
         if ($this->properties[DB::DRIVER] == 'mysql') {
             if ($this->properties[DB::SSL_CA]) {
                 $parameters["driverOptions"][\PDO::MYSQL_ATTR_SSL_CA] = \OC::$SERVERROOT . '/' . $this->properties[DB::SSL_CA];