Thanks. Not sure why Sipdroid did not come up when I searched earlier. Installed it now, will see if I can get it to connect to our Kerio Operator PBX.
FWIW, Sipdroid would not register with our Kerio Operator PBX. I didn’t spend more than 5 minutes on it, because I tried Linphone and it connected no problem, only thing I had to change was supported codecs so they matched the Operator server. Thanks to @Vaughan for the suggestions!
I’ve been through that and everything else with no luck. It will receive calls for a while after the screen goes blank but within an hour you can bet it won’t wake up when an incoming call arrives. I might look again at Linphone and others if there’s ever a problem with SipDroid, but for now it’s reliable enough to stick with it.