diff --git a/Tests/PhotoUploadFlowTest.php b/Tests/PhotoUploadFlowTest.php
index a10f41ee..968e6563 100644
--- a/Tests/PhotoUploadFlowTest.php
+++ b/Tests/PhotoUploadFlowTest.php
@@ -16,6 +16,14 @@ class PhotoUploadFlowTest extends IntegrationTestCase {
 
 	const IMAGE = '/Fixtures/blue-pixel.png';
 
+	protected function setUp() : void {
+		if (\version_compare(\PHP_VERSION, '7.4', '<') && ($_ENV['DB_FLAVOR'] ?? '') === 'postgresql') {
+			$this->markTestSkipped('Would fail because SerializableFile::__serialize is only supported as of PHP 7.4.');
+		}
+
+		parent::setUp();
+	}
+
 	public function testPhotoUpload() {
 		$image = __DIR__ . self::IMAGE;
 
diff --git a/Tests/Storage/DataManagerIntegrationTest.php b/Tests/Storage/DataManagerIntegrationTest.php
index e09111fd..b2c6d0c8 100644
--- a/Tests/Storage/DataManagerIntegrationTest.php
+++ b/Tests/Storage/DataManagerIntegrationTest.php
@@ -26,6 +26,10 @@ class DataManagerIntegrationTest extends IntegrationTestCase {
 	 * Ensure that a file uploaded within a flow is saved and restored correctly.
 	 */
 	public function testSaveLoad_file() : void {
+		if (\version_compare(\PHP_VERSION, '7.4', '<') && ($_ENV['DB_FLAVOR'] ?? '') === 'postgresql') {
+			$this->markTestSkipped('Would fail because SerializableFile::__serialize is only supported as of PHP 7.4.');
+		}
+
 		$session = new Session(new MockArraySessionStorage());
 		$session->setId('12345');