Use a tag since it now contains needed changes

Author: OlegL

composer.json

@@ -33,7 +33,7 @@
   },
   "require":     {
     "dreamfactory/df-core":   "~0.14.0",
-    "dreamfactory/df-system": "dev-feature/update-server"
+    "dreamfactory/df-system": "~0.2.0"
   },
   "autoload":    {
     "psr-4": {