@u4iia you can break a network switch upgrade into stages now. Once you schedule the upgrade there is an option under Switch / Staged Upgrades where you can edit the schedule and add additional upgrade windows:
I have successfully used this on a stack of three MS355X switches to upgrade the master first and then the other two switches 5 minutes later. I was onsite and it did follow the plan with no obvious negative issues.
I have also used it on non-stacked switches many times without a problem.
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