diff --git a/composer.json b/composer.json
index 820a826..9aaefc9 100644
--- a/composer.json
+++ b/composer.json
@@ -19,7 +19,7 @@
     "require-dev": {
         "graham-campbell/testbench": "~3.0",
         "mockery/mockery": "^0.9.4",
-        "phpunit/phpunit": "^4.7.6"
+        "phpunit/phpunit": "^4.8|^5.0"
     },
     "autoload": {
         "psr-4": {