diff --git a/README.md b/README.md
index 3d67eb6..82d4feb 100644
--- a/README.md
+++ b/README.md
@@ -105,6 +105,10 @@ Wikibase Internal Serialization has been written by
 
 ## Release notes
 
+### 2.9.0 (2018-11-06)
+
+* Added compatibility with Wikibase DataModel 9.x
+
 ### 2.8.0 (2018-08-07)
 
 * Added compatibility with Wikibase DataModel 8.x
diff --git a/composer.json b/composer.json
index 04c103d..c94f97c 100644
--- a/composer.json
+++ b/composer.json
@@ -44,7 +44,7 @@
 	},
 	"extra": {
 		"branch-alias": {
-			"dev-master": "2.8.x-dev"
+			"dev-master": "2.9.x-dev"
 		}
 	},
 	"scripts": {