Hello BCasey,
After the licenses upload, you will have to restart the CallManager service.
No phones will be reboot during the process - rest assured.
during the service restart, your phones will still be registered with the Subscriber. (They were still registered to the subs before reboot, and will be registered there itself even after )
During the restart, your CM database will be in read-only mode (Subscriber only is active):
This will not affect your phone operations.
This will only affect device profile logins and logouts. If the profiles are already logged on, it will not affect. If you are trying to login or logout during the Publisher CM service is down, this will be affected.
-NO downtime on phone
-No downtime on telephony service
-No modification can be performed on Call Manager when Publisher Call Manager is down
-NO login/logout can be performed when Pub CM service is down.
After the Pub service is back UP, you can work normally as before.
Thanks
Nitish