It is important if you are implementing a filter mode application that you include End Call events in your filter.

The end call events are recognized by the CIL (Client Interface Library) to know to release the call object. If you don't include the end call event in your filter, the CIL will not see that event (it will not be sent to the Client by the CTIOS Server) and consequently the CIL will not know to release the call object. This will cause the memory used by the CIL for call objects to continue growing, eventually crashing your application.