I've just received this on a network where the switches are running 15.10, not sure what happened with 15.11 and 15.12...
On April 25, 2022, between 3:00 AM and 5:00 AM BST, the firmware for the switch in the network "" will be upgraded to MS 15.12.1.
The new firmware includes support for the following features:
- Important notice
- This upgrade addresses an uncommon but critical scenario where one or multiple switches in an MS390 stacked configuration may not recover from a system reboot if running releases 15.1 to 15.11. We highly recommend upgrading to MS15.12+ as soon as possible, which safely addresses this issue.