Siemens S55/S25: delivered messages are not triggered

Q: It's not possible to receive delivered message from Siemens S55/S25. Periodical checking using GetSMSList is working.

A: Seems that Siemens S55 does not notify application when uindOnlyIndication is inactive. Set

  UnsolicitedIndication:= [uindSMSDeliver, uindOnlyIndication, ...];