diff --git a/composer.json b/composer.json
index 54432f5..8d946f9 100644
--- a/composer.json
+++ b/composer.json
@@ -4,7 +4,7 @@
     "type": "library",
     "require": {
         "php": ">=7.1",
-        "guzzlehttp/guzzle": "~7"
+        "guzzlehttp/guzzle": "~6.5.8"
     },
     "license": "MIT",
     "autoload": {