I am adding another stack at one of our locations. The new switches used in the new stack our running 21.1.1.4 patch1-2. The other two stacks at the location are running 15.6.2.12 patch1-6, and 15.5.3.4 patch1-6. I would like to upgrade the XOS in the other stacks during the outage, to the same version as the new stack (21.1.1.4 patch1-2), or higher if you recommend another version.
My questions are:
1. Will the new version need to be installed on each stack slot, or just once to the stack. Will each node need to be rebooted separately, or as a whole stack?
2. Are there any known issues upgrading from the above versions to the new one? There are no special configurations in the switches, just VLANs and IP forwarding. On stack is a transit node in an EAPS ring.
3. SSH is installed and enabled, SSH used to be a separate download and install. Since it is now part of the XOS in version 21.X, are there any additional steps, or will it be enabled from the existing configuration? Will a new key need to be generated after the reboot?
4. If there are issues that we are unable to resolve during our outage window, are there, or will there be, any issues reverting to the currently running XOS?
