API that was marked as deprecated in RAP 2.x has been removed. This includes API related to lifecycle phases and lifecycle adapters (LCAs), concepts which we consider internals of the framework. Custom widgets should use the new Remote API instead.
The RAP 3.0 Migration Guide contains a comprehensive description of the API changes, and describes ways to migrate applications based on RAP 2.x to RAP 3.0.
RAP 3.0 requires Internet Explorer 9 or above. Support for Internet Explorer 8 has been dropped.