Yeah, read about it here too (January 2017).
Would be great to read about reproducible time metrics (how long does the entire sequenced update take? impact on Layer 2 and Layer 3 traffic in case of dual homed access devices/hosts? best practices with related to booting into secondary instead of updating primary? behaviour for upgrades between different software lines - 16.05.xxxx -> 16.06.yyyy versus updates within the same software line - 16.05.nnnn -> 16.05.mmmm - and other possible questions).