diff --git a/split-repository/composer.json b/split-repository/composer.json
index e2c215f938..c0a567eda8 100644
--- a/split-repository/composer.json
+++ b/split-repository/composer.json
@@ -2,7 +2,8 @@
     "require": {
         "knplabs/github-api": "^3.0",
         "guzzlehttp/guzzle": "^7.0.1",
-        "http-interop/http-factory-guzzle": "^1.0"
+        "http-interop/http-factory-guzzle": "^1.0",
+        "psr/http-message": "~1.0"
     },
     "autoload": {
         "psr-4": {
@@ -14,4 +15,4 @@
             "php-http/discovery": false
         }
     }
-}
+}
\ No newline at end of file