1. Must I unplug hardwire & clear network before upgrading?generally network failover won't work when upgrading major version (e.g. 10.x to 11.x) but hardware failover still works (i.e. can control active/standby state) because it does not use heartbeat packet. actually, disabling/unplugging network failover is to prevent service interruption (e.g. active/active situation) while upgrading. if you disconnect all network cables from one of units, even units go active/active it won't cause service interruption.
2. In 11.2.1 , If I have both HW & Network failover, Failover will occur when HardWire & NW failover cannot detect their signal. right?hardware failover has higher precedence. failover should not happen while upgrading.