diff --git a/composer.json b/composer.json
index 289c7bd..696d07b 100644
--- a/composer.json
+++ b/composer.json
@@ -14,10 +14,10 @@
 		}
 	],
 	"require": {
-		"guzzlehttp/guzzle": "^6.0"
+		"guzzlehttp/guzzle": "3.8 - 6.5"
 	},
 	"require-dev": {
-		"phpunit/phpunit": "4.0.*"
+		"phpunit/phpunit": "4.8 - 5"
 	},
 	"autoload": {
 		"psr-4": {