diff --git a/composer.json b/composer.json
index f9f6a179d..fb1cd3bfc 100644
--- a/composer.json
+++ b/composer.json
@@ -46,7 +46,7 @@
         "php-di/php-di": "^6.4",
         "slim/psr7": "^1.7",
         "bacon/bacon-qr-code": "^3.0",
-        "seeddms/core": "dev-master",
+        "seeddms/core": "dev-seeddms-5.1.x",
         "seeddms/lucene": "dev-master",
         "seeddms/preview": "dev-master",
         "seeddms/sqlitefts": "dev-master",