Cat3k 3850 stack IOS-XE Upgrade question

[darthnul]

I have a stack of three cat 3850 switches running IOS-XE 3.03.00SE.  I need to upgrade them to 3.03.05SE to resolve outstanding security bulletins.

Most of the devices connecting to the stack have redundant connections to two different switches in the stack.

Is it possible to upgrade the switch software and reboot the switches one at a time in order to maintain connectivity for the devices with redundant connections?  I've been looking at upgrade docs including http://www.cisco.com/c/en/us/support/docs/switches/catalyst-3850-series-switches/117552-technote-cat3850-00.pdf ; but I don't see this addressed.  Back when we bought this hardware, our Cisco account mgr said this would be possible, but I have not been able to verify it.

[Reza Sharifi · Accepted solution]

Is it possible to upgrade the switch software and reboot the switches one at a time in order to maintain connectivity for the devices with redundant connections?

That is not currently possible.  You would have to load the new image in all switches and reboot the entire stack.

HTH