Just a quick reminder to those using the UseCallManager patch with their Cisco phones. At this time you have about 4 years to decide on a course of action. There are three courses of action, as I see it, you can take.
Stay on Asterisk v20 or lower for the reminder of life you have the Cisco phones. Chan_SIP isn’t going to exist in v21 or higher.
Move to chan_pjsip and lose a serious amount of features/functionality of the phone and accept that to continue using the phones.
Replace the Cisco phones.
Of course you could hope that after almost a decade of chan_pjsip the author decides to actually migrate it to chan_pjsip but I don’t see that happening.