Which firmware upgrade method for an active-passive HA cluster ensures service outage is minimal, and there are no unnecessary failovers?

Which firmware upgrade method for an active-passive HA cluster ensures service outage is minimal, and there are no unnecessary failovers?
A . Break the cluster, upgrade the units independently, and then form the cluster
B . Upgrade both units at the same time
C . Upgrade the standby unit, and then upgrade the active unit
D . Upgrade the active unit, which will upgrade the standby unit automatically

View Answer

Answer: B

Explanation:

Reference: https://docs.fortinet.com/document/fortimail/6.2.0/administration-guide/725928/upgrading-firmware- on-ha-units