diff --git a/composer.json b/composer.json
index cd66c3c..23c31ff 100644
--- a/composer.json
+++ b/composer.json
@@ -16,7 +16,7 @@
     ],
     "minimum-stability": "stable",
     "require": {
-        "effectra/http-message": "^2.0",
+        "effectra/http-message": "1.0",
         "psr/http-factory": "^1.0"
     }
 }