Communication networks and methods are disclosed that synchronize call feature data between an IMS network and a legacy network, such as a cellular network. An IMS subscriber server (e.g., a Home Subscriber Server (HSS)) is notified of changes to feature data for a call feature (e.g., call forwarding, call waiting, etc) in the IMS network. Responsive to the notification, the IMS subscriber server updates a legacy subscriber server (e.g., a Home Location Register (HLR)) in the legacy network based on the change to the feature data. Similarly, the IMS subscriber server identifies changes to feature data for a call feature in the legacy network. Responsive to the change, the IMS subscriber server notifies one or more application servers in the IMS network of the change to the feature data. Through the IMS subscriber server, feature data for call features is synchronized between the IMS network and the legacy network.