diff --git a/composer.json b/composer.json
index 6a9aa80..9686cc7 100644
--- a/composer.json
+++ b/composer.json
@@ -24,7 +24,7 @@
         "php": ">=5.6",
         "psr/cache": "^1",
         "psr/log": "^1",
-        "php-http/client-implementation": "^1.0",
+        "php-http/client-implementation": "^1.0|^2.0",
         "php-http/httplug": "^1.0",
         "php-http/discovery": "^1.0",
         "php-http/message": "^1.0"