diff --git a/composer.json b/composer.json
index 2ffc646..f31a5a3 100644
--- a/composer.json
+++ b/composer.json
@@ -37,7 +37,7 @@
     "type": "library",
     "require": {
         "php": ">=5.5.9",
-        "guzzlehttp/guzzle": "~6"
+        "guzzlehttp/guzzle": "~6|~7"
     },
     "require-dev": {
         "phpunit/phpunit": "5.7"