diff --git a/composer.json b/composer.json
index e4f1ed9..7c5a4f4 100644
--- a/composer.json
+++ b/composer.json
@@ -28,7 +28,7 @@
         "php": "^7.1 || ^8"
     },
     "require-dev": {
-        "sminnee/phpunit": "^5.7",
+        "phpunit/phpunit": "^9",
         "squizlabs/php_codesniffer": "^3.0"
     },
     "extra": {
diff --git a/tests/CronTaskControllerTest.php b/tests/CronTaskControllerTest.php
index 1d0559d..6fd1634 100644
--- a/tests/CronTaskControllerTest.php
+++ b/tests/CronTaskControllerTest.php
@@ -24,7 +24,7 @@ class CronTaskControllerTest extends FunctionalTest
     /**
      * {@inheritDoc}
      */
-    protected function setUp()
+    protected function setUp(): void
     {
         parent::setUp();
         CronTaskTest\TestCron::$times_run = 0;