Switch Stacks
Switch stacks are treated as a single device when it comes to upgrades. That is, every switch in a particular switch stack must belong to the same upgrade group. Therefore, you assign the stack to the group rather than each switch.
Switch stacks can be expanded in the group member list to see details about the switches that belong to that stack.
https://documentation.meraki.com/MS/Firmware/MS_Firmware_Upgrades
I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.
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