diff --git a/composer.json b/composer.json
index 5b9c48a..221e5ca 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,7 @@
   "minimum-stability": "beta",
   "require": {
     "phing/phing": "~2.9",
-    "drush/drush": "^9.0"
+    "drush/drush": "^8.1.15 || ^9.0"
   },
   "autoload": {
     "psr-0": {