diff --git a/composer.json b/composer.json
index 33a64f51..fa5da09e 100644
--- a/composer.json
+++ b/composer.json
@@ -37,7 +37,7 @@
         "php-http/client-implementation": "^1.0",
         "php-http/discovery": "^1.14",
         "php-http/message-factory": "^1.0",
-        "psr/http-message": "^1.0"
+        "psr/http-message": "^1.0 || ^2.0"
     },
     "require-dev": {
         "guzzlehttp/psr7"       : "^2.0",