diff --git a/.github/workflows/cypress-e2e.yml b/.github/workflows/cypress-e2e.yml
index 1986e6da2..d086bc885 100644
--- a/.github/workflows/cypress-e2e.yml
+++ b/.github/workflows/cypress-e2e.yml
@@ -24,7 +24,7 @@ jobs:
       matrix:
         node-version: [20.x]
         containers: [1, 2, 3]
-        php-versions: [ '8.2' ]
+        php-versions: [ '8.3' ]
         server-versions: [ 'master' ]
 
     name: runner ${{ matrix.containers }}
diff --git a/.github/workflows/integration-federation.yml b/.github/workflows/integration-federation.yml
index daf6bcc74..7ccd7ec52 100644
--- a/.github/workflows/integration-federation.yml
+++ b/.github/workflows/integration-federation.yml
@@ -29,7 +29,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php-versions: ['8.2']
+        php-versions: ['8.3']
         server-versions: ['master']
 
     name: php${{ matrix.php-versions }}-${{ matrix.server-versions }}
diff --git a/.github/workflows/integration.yml b/.github/workflows/integration.yml
index 0cca474ba..c31f2006d 100644
--- a/.github/workflows/integration.yml
+++ b/.github/workflows/integration.yml
@@ -30,7 +30,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php-versions: ['8.2']
+        php-versions: ['8.3']
         databases: ['sqlite', 'mysql', 'pgsql']
         server-versions: ['master']
 
diff --git a/lib/Service/FileService.php b/lib/Service/FileService.php
index 77c4953b0..df7bdbed8 100644
--- a/lib/Service/FileService.php
+++ b/lib/Service/FileService.php
@@ -83,7 +83,7 @@ public function extendData(Attachment $attachment) {
 	}
 
 	/**
-	 * @return array
+	 * @return array|null
 	 * @throws StatusException
 	 */
 	private function getUploadedFile() {
diff --git a/lib/Service/FilesAppService.php b/lib/Service/FilesAppService.php
index f11054dc3..75788ecf1 100644
--- a/lib/Service/FilesAppService.php
+++ b/lib/Service/FilesAppService.php
@@ -332,7 +332,7 @@ public function createFromImport(Attachment $attachment, string $content): Attac
 	}
 
 	/**
-	 * @return array
+	 * @return array|null
 	 * @throws StatusException
 	 */
 	private function getUploadedFile() {
diff --git a/lib/Service/PermissionService.php b/lib/Service/PermissionService.php
index 628e610e7..2f370fa45 100644
--- a/lib/Service/PermissionService.php
+++ b/lib/Service/PermissionService.php
@@ -303,7 +303,7 @@ public function findUsers($boardId, $refresh = false) {
 					continue;
 				}
 				foreach ($group->getUsers() as $user) {
-					$users[(string)$user->getUID()] = new User($user->getUID(), $this->userManager);
+					$users[$user->getUID()] = new User($user->getUID(), $this->userManager);
 				}
 			}
 
diff --git a/psalm.xml b/psalm.xml
index bd7ead736..2963f3fef 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -8,7 +8,7 @@
 		errorBaseline="tests/psalm-baseline.xml"
 		findUnusedBaselineEntry="true"
 		findUnusedCode="false"
-    	phpVersion="8.2"
+    	phpVersion="8.3"
 >
 	<stubs>
 		<file name="tests/stub.phpstub" preloadClasses="true"/>