diff --git a/composer.json b/composer.json
index f9764d70be..cec05c304c 100644
--- a/composer.json
+++ b/composer.json
@@ -154,6 +154,9 @@
         "src-dir": "src",
         "var-dir": "var",
         "public-dir": "web",
+        "branch-alias": {
+            "dev-master": "9.1.x-dev"
+        },
         "symfony": {
             "allow-contrib": true,
             "require": "^4.4"