diff --git a/composer.json b/composer.json
index 361648a3..9da67230 100644
--- a/composer.json
+++ b/composer.json
@@ -22,7 +22,7 @@
         "nesbot/carbon": "~1.20||^1.26.3||^2.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "~8.0||~9.0",
+        "phpunit/phpunit": "~5.0||~6.0||~7.0||~8.0||~9.0",
         "mockery/mockery": "^1.0",
         "orchestra/testbench": "^3.4|^4.0|^5.0|^6.0"
     },