diff --git a/composer.json b/composer.json
index f77a698..daec316 100644
--- a/composer.json
+++ b/composer.json
@@ -40,7 +40,7 @@
         "mezzio/mezzio-authentication": "^1.0",
         "psr/container": "^1.0 || ^2.0",
         "psr/http-factory": "^1.0",
-        "psr/http-message": "^1.0.1",
+        "psr/http-message": "^1.0.1 || ^2.0.0",
         "psr/http-server-middleware": "^1.0",
         "webmozart/assert": "^1.10"
     },