Which of the following statements about the features of the firewall hot standby system version upgrade is incorrect?

Which of the following statements about the features of the firewall hot standby system version upgrade is incorrect?
A . When a bug occurs in the live network fire protection system version, the system version needs to be upgraded.
B . When the existing network fire protection system version does not support certain features, the system version needs to be upgraded.
C . Version upgrade has requirements for the device model and version before the upgrade
D . When upgrading the dual-machine hot audio version, the rule of thumb is to upgrade the Active device first, and then upgrade the Standby device.

Answer: D