diff --git a/composer.json b/composer.json
index 26d355e..765a14a 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,7 @@
 
 	"require": {
 		"php": ">=5.3.3",
-		"phpunit/phpunit": "~4.8",
+		"phpunit/phpunit": "^4.8 || ^5.7",
 		"behat/behat": "~2.5.0",
 		"behat/mink": "~1.6.0",
 		"behat/mink-extension": "~1.3.0",