diff --git a/webapp/tests/Unit/Controller/API/ClarificationControllerTest.php b/webapp/tests/Unit/Controller/API/ClarificationControllerTest.php
index a71ed36965..cb02f0099b 100644
--- a/webapp/tests/Unit/Controller/API/ClarificationControllerTest.php
+++ b/webapp/tests/Unit/Controller/API/ClarificationControllerTest.php
@@ -143,7 +143,7 @@ public function testAddInvalidData(string $user, array $dataToSend, string $expe
     public function provideAddInvalidData(): Generator
     {
         yield ['demo', [], ""];
-        yield ['demo', ['invalidfield' => 'value'], "/text:\n.*This value should be of type unknown./"];
+        yield ['demo', ['invalidfield' => 'value'], "/text:\n.*This value should be of type string./"];
         yield ['demo', ['text' => 'This is a clarification', 'from_team_id' => 'domjudge'], "Can not create a clarification from a different team."];
         yield ['demo', ['text' => 'This is a clarification', 'to_team_id' => 'exteam'], "Can not create a clarification that is sent to a team."];
         yield ['demo', ['text' => 'This is a clarification', 'problem_id' => 'prob'], "Problem 'prob' not found."];
diff --git a/webapp/tests/Unit/Controller/API/ContestControllerAdminTest.php b/webapp/tests/Unit/Controller/API/ContestControllerAdminTest.php
index 3acc00496a..5655e97c80 100644
--- a/webapp/tests/Unit/Controller/API/ContestControllerAdminTest.php
+++ b/webapp/tests/Unit/Controller/API/ContestControllerAdminTest.php
@@ -274,7 +274,7 @@ public function provideChangeTimes(): Generator
 
         // General tests
         yield [[], 400, ''];
-        yield [['dummy' => 'dummy'], 400, "This value should be of type unknown."];
+        yield [['dummy' => 'dummy'], 400, "This value should be of type string."];
         yield [['id' => 1], 400, 'Missing \"start_time\" or \"scoreboard_thaw_time\" in request.'];
         yield [['id' => 1, 'start_time' => null, 'scoreboard_thaw_time' => date('Y-m-d\TH:i:s', strtotime('+15 seconds'))], 400, 'Setting both \"start_time\" and \"scoreboard_thaw_time\" at the same time is not allowed.'];
 
diff --git a/webapp/tests/Unit/Controller/API/SubmissionControllerTest.php b/webapp/tests/Unit/Controller/API/SubmissionControllerTest.php
index 8d3f3c53c8..c255ff498c 100644
--- a/webapp/tests/Unit/Controller/API/SubmissionControllerTest.php
+++ b/webapp/tests/Unit/Controller/API/SubmissionControllerTest.php
@@ -107,7 +107,7 @@ public function provideAddInvalidData(): Generator
         yield ['demo', ['problem_id' => 'hello', 'language_id' => 'cpp', 'id' => '123'], "A team can not assign id."];
         yield ['demo', ['problem_id' => 'hello', 'language_id' => 'cpp', 'time' => '2021-01-01T00:00:00'], "A team can not assign time."];
         yield ['demo', ['problem_id' => 'hello', 'language_id' => 'cpp', 'files' => []], "No files specified."];
-        yield ['demo', ['problem_id' => 'hello', 'language_id' => 'cpp', 'files' => [['invalidkey' => 'somevalue']]], "/files\[0\].data:\n.*This value should be of type unknown./"];
+        yield ['demo', ['problem_id' => 'hello', 'language_id' => 'cpp', 'files' => [['invalidkey' => 'somevalue']]], "/files\[0\].data:\n.*This value should be of type string./"];
         yield [
             'demo',
             ['problem_id' => 'hello', 'language_id' => 'cpp', 'files' => 'this is not an array'],
diff --git a/webapp/tests/Unit/Controller/API/UserControllerTest.php b/webapp/tests/Unit/Controller/API/UserControllerTest.php
index 33629e5c4e..fc92392a2e 100644
--- a/webapp/tests/Unit/Controller/API/UserControllerTest.php
+++ b/webapp/tests/Unit/Controller/API/UserControllerTest.php
@@ -91,6 +91,6 @@ public function testUpdateNoId(): void
         ];
 
         $response = $this->verifyApiJsonResponse('PUT', $this->helperGetEndpointURL($this->apiEndpoint) . '/someid', 400, 'admin', $data);
-        static::assertMatchesRegularExpression('/id:\n.*This value should be of type unknown./', $response['message']);
+        static::assertMatchesRegularExpression('/id:\n.*This value should be of type string./', $response['message']);
     }
 }