Have been waiting for less trouble and finally updated last week from 4.7.3 to 5.16a.... followed hart2hart's check list below. Upgrade went flawlessly with exception of leak sensors. Just upgrades to 5.16b. Again no issues. Waiting 24 hours for heartbeat to know for sure.  One additional tip / idea  to the list below: - I have historically had issues with certain programs that should be disabled, becoming enabled due to power outages etc. and have always had a challenge going through