diff --git a/composer.json b/composer.json
index 6cca5672..44b01f92 100644
--- a/composer.json
+++ b/composer.json
@@ -42,10 +42,9 @@
         "jakub-onderka/php-parallel-lint": "^0.9.2",
         "phpro/grumphp": "^0.11.6",
         "phpstan/phpstan": "^0.8",
-        "phpunit/phpunit": "^5.7",
-        "sensiolabs/security-checker": "^4.1",
-        "sebastian/phpcpd": "^3.0"
         "phpunit/phpunit": "^6.0.13",
+        "sebastian/phpcpd": "^3.0",
+        "sensiolabs/security-checker": "^4.1"
     },
     "bin": [
         "bin/bunq-install"