diff --git a/composer.json b/composer.json
index da5ccb0..e7e6153 100644
--- a/composer.json
+++ b/composer.json
@@ -16,6 +16,6 @@
         }
     ],
     "require": {
-        "guzzlehttp/guzzle": "^7.0"
+        "guzzlehttp/guzzle": "^6.0 || ^7.0"
     }
 }