diff --git a/composer.json b/composer.json
index e6af602..84b6cdd 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,7 @@
 	}
     ],
     "require": {
-	"php": ">=4"
+	"php": ">=5.6"
     },
     "scripts": {
         "serve": ["@php -S localhost:29896 bibtexbrowser.php"]