diff --git a/composer.json b/composer.json
index f36524e..d9a7c18 100644
--- a/composer.json
+++ b/composer.json
@@ -14,7 +14,7 @@
   ],
    "require": {
      "php": ">= 5.5",
-     "guzzlehttp/guzzle": "~6.0"
+     "guzzlehttp/guzzle": "^6.0 | ^7.0"
    },
    "require-dev": {
      "phpunit/phpunit": "4.5.*"