diff --git a/composer.json b/composer.json
index f152a309..13e18394 100644
--- a/composer.json
+++ b/composer.json
@@ -19,6 +19,9 @@
     "silverstripe/framework": "^4.0@dev",
     "silverstripe/admin": "^1.0@dev"
   },
+  "require-dev": {
+    "phpunit/phpunit": "^5.7"
+  },
   "extra": {
     "branch-alias": {
       "dev-master": "4.0.x-dev"
@@ -33,8 +36,5 @@
   "scripts": {
     "lint": "phpcs code/ tests/",
     "lint-clean": "phpcbf code/ tests/"
-  },
-  "require-dev": {
-    "phpunit/PHPUnit": "~4.8"
   }
 }