diff --git a/.github/workflows/package.yml b/.github/workflows/package.yml
index b4c6deee06785474888d2757ba7e70903da0086e..b9412e7bed746d178479074a07c410b97ced0093 100644
--- a/.github/workflows/package.yml
+++ b/.github/workflows/package.yml
@@ -4,7 +4,7 @@ on: [push, pull_request]
 
 jobs:
   release-tarball:
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     name: Build release tarball
     steps:
       - name: Checkout
@@ -22,8 +22,8 @@ jobs:
           coverage: none
       - name: Install Krankerl
         run: |
-          wget https://github.com/ChristophWurst/krankerl/releases/download/v0.12.3/krankerl_0.12.3_amd64.deb
-          sudo dpkg -i krankerl_0.12.3_amd64.deb
+          wget https://github.com/ChristophWurst/krankerl/releases/download/v0.14.0/krankerl_0.14.0_amd64.deb
+          sudo dpkg -i krankerl_0.14.0_amd64.deb
       - name: Package app
         run: krankerl package
       - uses: actions/upload-artifact@v2
diff --git a/.github/workflows/php-test.yml b/.github/workflows/php-test.yml
index b8d2a931098e23926874aa3c977268bf8975cc1d..7fef20f0172016e4a6dfe6c59810e1efaedffb30 100644
--- a/.github/workflows/php-test.yml
+++ b/.github/workflows/php-test.yml
@@ -20,12 +20,6 @@ jobs:
             nextcloud-versions: 'stable24'
           - php-versions: '8.1'
             nextcloud-versions: 'stable24'
-          - php-versions: '7.4'
-            nextcloud-versions: 'master'
-          - php-versions: '8.0'
-            nextcloud-versions: 'master'
-          - php-versions: '8.1'
-            nextcloud-versions: 'master'
     name: php${{ matrix.php-versions }} on ${{ matrix.nextcloud-versions }} unit tests
     env:
       CI: true
diff --git a/CHANGELOG.md b/CHANGELOG.md
index b64cf20c88521b7f26aff72b189af1bcaf3ced32..bbb124b9609e75df0d056b73d6a9c3771197c545 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,10 @@
 
 # Changelog
 
+## 3.5.5 - 2023-02-01
+### Fixed
+- Error handling in booking controller
+
 ## 3.5.4 - 2022-12-22
 ### Fixed
 - Handling of Email VALARMs
diff --git a/appinfo/info.xml b/appinfo/info.xml
index 195c859c98ff72c11baf5cbff4251033fa851f9b..2f1757145ac1a19f85fa31fcb9080b8bb21363ef 100644
--- a/appinfo/info.xml
+++ b/appinfo/info.xml
@@ -15,7 +15,7 @@
 * ☑️ Tasks! See tasks with a due date directly in the calendar
 * 🙈 **We’re not reinventing the wheel!** Based on the great [c-dav library](https://github.com/nextcloud/cdav-library), [ical.js](https://github.com/mozilla-comm/ical.js) and [fullcalendar](https://github.com/fullcalendar/fullcalendar) libraries.
 	]]></description>
-	<version>3.5.4</version>
+	<version>3.5.5</version>
 	<licence>agpl</licence>
 	<author>Anna Larch</author>
 	<author homepage="https://github.com/nextcloud/groupware">Nextcloud Groupware Team</author>
diff --git a/lib/Controller/BookingController.php b/lib/Controller/BookingController.php
index a8a564c2decb1e42ed527b368f2fadd1a80e8c28..4339c14308b068fef05f4aec240632b2014cb37d 100644
--- a/lib/Controller/BookingController.php
+++ b/lib/Controller/BookingController.php
@@ -42,6 +42,7 @@ use OCP\AppFramework\Http\TemplateResponse;
 use OCP\AppFramework\Services\IInitialState;
 use OCP\AppFramework\Utility\ITimeFactory;
 use OCP\DB\Exception;
+use OCP\IConfig;
 use OCP\IRequest;
 use OCP\Mail\IMailer;
 use Psr\Log\LoggerInterface;
@@ -68,6 +69,7 @@ class BookingController extends Controller {
 
 	/** @var IMailer */
 	private $mailer;
+	private IConfig $systemConfig;
 
 	public function __construct(string $appName,
 								IRequest $request,
@@ -77,7 +79,8 @@ class BookingController extends Controller {
 								AppointmentConfigService $appointmentConfigService,
 								URLGenerator $urlGenerator,
 								LoggerInterface $logger,
-								IMailer $mailer) {
+								IMailer $mailer,
+								IConfig $systemConfig) {
 		parent::__construct($appName, $request);
 
 		$this->bookingService = $bookingService;
@@ -87,6 +90,7 @@ class BookingController extends Controller {
 		$this->urlGenerator = $urlGenerator;
 		$this->logger = $logger;
 		$this->mailer = $mailer;
+		$this->systemConfig = $systemConfig;
 	}
 
 	/**
@@ -191,7 +195,17 @@ class BookingController extends Controller {
 			return JsonResponse::fail(null, Http::STATUS_UNPROCESSABLE_ENTITY);
 		} catch (ServiceException $e) {
 			$this->logger->error($e->getMessage(), ['exception' => $e]);
-			return JsonResponse::errorFromThrowable($e, $e->getHttpCode() ?? Http::STATUS_INTERNAL_SERVER_ERROR);
+
+			if ($this->systemConfig->getSystemValue('debug', false)) {
+				return JsonResponse::errorFromThrowable($e, $e->getHttpCode() ?? Http::STATUS_INTERNAL_SERVER_ERROR,
+					['debug' => true,]
+				);
+			}
+
+			return JsonResponse::error(
+				'Server error',
+				$e->getHttpCode() ?? Http::STATUS_INTERNAL_SERVER_ERROR
+			);
 		}
 
 		return JsonResponse::success($booking);
diff --git a/package-lock.json b/package-lock.json
index 48205b81d5428790b9b524984f6a43ee0d6474c7..bed327aa5683e9d96001708a90f83f2153b7a631 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "calendar",
-  "version": "3.5.4",
+  "version": "3.5.5",
   "lockfileVersion": 2,
   "requires": true,
   "packages": {
     "": {
       "name": "calendar",
-      "version": "3.5.4",
+      "version": "3.5.5",
       "license": "agpl",
       "dependencies": {
         "@fullcalendar/core": "5.11.0",
diff --git a/package.json b/package.json
index b4067d429cffeeee6394285c13d2007717319ad3..fc97e1175fbd3f0a1145a2572b0ea20da9bea09c 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "calendar",
   "description": "A calendar app for Nextcloud. Easily sync events from various devices, share and edit them online.",
-  "version": "3.5.4",
+  "version": "3.5.5",
   "author": "Georg Ehrke <oc.list@georgehrke.com>",
   "contributors": [
     "Georg Ehrke <oc.list@georgehrke.com>",
diff --git a/tests/php/unit/Controller/BookingControllerTest.php b/tests/php/unit/Controller/BookingControllerTest.php
index 529cc2f49fbaf9fc9a6c0134ba650e0c96280e7f..5c60cc283d75551ac95b7c6e47b222f88af5d6f8 100644
--- a/tests/php/unit/Controller/BookingControllerTest.php
+++ b/tests/php/unit/Controller/BookingControllerTest.php
@@ -39,6 +39,7 @@ use OCP\AppFramework\Services\IInitialState;
 use OCP\AppFramework\Utility\ITimeFactory;
 use OCP\Calendar\ICalendarQuery;
 use OCP\Contacts\IManager;
+use OCP\IConfig;
 use OCP\IInitialStateService;
 use OCP\IRequest;
 use OCP\IUser;
@@ -88,6 +89,9 @@ class BookingControllerTest extends TestCase {
 	/** @var IMailer|MockObject */
 	private $mailer;
 
+	/** @var IConfig|MockObject  */
+	private $systemConfig;
+
 	protected function setUp():void {
 		parent::setUp();
 
@@ -104,6 +108,7 @@ class BookingControllerTest extends TestCase {
 		$this->urlGenerator = $this->createMock(URLGenerator::class);
 		$this->logger = $this->createMock(LoggerInterface::class);
 		$this->mailer = $this->createMock(IMailer::class);
+		$this->systemConfig = $this->createMock(IConfig::class);
 		$this->controller = new BookingController(
 			$this->appName,
 			$this->request,
@@ -113,7 +118,8 @@ class BookingControllerTest extends TestCase {
 			$this->apptService,
 			$this->urlGenerator,
 			$this->logger,
-			$this->mailer
+			$this->mailer,
+			$this->systemConfig,
 		);
 	}
 
@@ -255,6 +261,10 @@ class BookingControllerTest extends TestCase {
 			->method('book')
 			->with($config, 1, 1, 'Europe/Berlin', 'Test', $email, 'Test')
 			->willThrowException(new ServiceException());
+		$this->systemConfig->expects(self::once())
+			->method('getSystemValue')
+			->with('debug')
+			->willReturn(false);
 
 		$this->controller->bookSlot(1, 1, 1, 'Test', $email, 'Test', 'Europe/Berlin');
 	}