OS10 license backup format vs installation format

Hi,

Documentation suggests when backing up a license you get a ".lic" file.

But all the documentation I've seen for restoring/installing a license in OS10 suggests you need a ".xlm" format.

What gives? I mean, imagine I have a switch with a current active license (permanent) and I want to backup said licence to install after an OS upgrade, since the upgrade procedure wipes your current the license.