diff --git a/composer.json b/composer.json
index 1051453..9d3c61a 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,7 @@
     "require": {
         "php": "^7.1",
         "squizlabs/php_codesniffer": "^3.0.0",
-        "slevomat/coding-standard": "^5.0"
+        "slevomat/coding-standard": "^5.0 || ^6.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^5.7"