This table identifies supported firmware version upgrade and downgrade paths.
For example, downgrading from firmware version 2.2.7 to 2.1.6 is supported, if the switch is configured with an older management controller. However, downgrading directly from firmware version 2.2.7 to 2.1.2 is not supported. If the switch is configured with an older management controller, you must first downgrade from firmware version 2.2.7 to 2.1.6 using the downgrade version of firmware 2.1.6. Then you can downgrade from 2.1.6 to 2.1.2.
See Firmware Update Guidelines about upgrading and downgrading firmware.