I am upgrading a CUCm that does NOT have any subscribers. I have downloaded the upgarde to the call Manager and my plan was to reboot later not immediately after the upgrade.My question is from this point if I choose to continue does the phones service interruption to the users while the upgarde is upacking? Should I not continue until after hours. this has never been an issue for me as there are usually subcribers in the cluster to take over if necessary. Input is appreciated!