[Freeswitch-users] Implement PushKit or CallKit to call iOS app closed

Hi, I can't find any information over how to implement PushKit or Callkit to call an iOS mobile phone that has the SIP client application closed or in the background. When the application is closed it is obviously that SIP account isn't registered and the FS server no send the call. Has anyone worked with this or know how to implement it? I tried with "<variable name="sip-force-contact" value="NDLB-connectile-dysfunction"/>" option and this temporally solved when the application is alive in background. Thanks,