diff --git a/composer.json b/composer.json
index 7329c5e5..2dc72ed4 100644
--- a/composer.json
+++ b/composer.json
@@ -29,7 +29,7 @@
 		"mrclay/jsmin-php": "~2",
 		"mrclay/props-dic": "^2.2",
 		"php": "^5.3.0 || ^7.0",
-		"tubalmartin/cssmin": "~2.4.8-p5"
+		"tubalmartin/cssmin": "^3.1"
 	},
 	"require-dev": {
 		"firephp/firephp-core": "~0.4.0",