diff --git a/composer.json b/composer.json
index 1f983fe..f43830d 100644
--- a/composer.json
+++ b/composer.json
@@ -23,8 +23,8 @@
     },
     "require-dev": {
         "larapack/dd": "^1.0",
-        "orchestra/testbench": "~3.5",
-        "phpunit/phpunit": "^7.0",
+        "orchestra/testbench": "~3.5|~3.6|~3.7|~3.8|^4.0",
+        "phpunit/phpunit": "^7.0| ^8.0",
         "spatie/phpunit-snapshot-assertions": "^1.3"
     },
     "autoload": {
diff --git a/tests/TestCase.php b/tests/TestCase.php
index a1b6ffe..a5210b6 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -7,7 +7,7 @@
 
 abstract class TestCase extends \Orchestra\Testbench\TestCase
 {
-    public function setUp()
+    public function setUp(): void
     {
         parent::setUp();