I recently picked a set of 2nd-hand Yuns, and was wondering if there was a quick way (i.e. by webportal or by command line) to check the current version of a Yun's firmware.
I quick search didn't come up with answer. Would like to avoid having to upgrade them, if I don't need to.
I doubt it. You may get lucky and find a modification date on some key files that may give you a clue when the image was installed, but I'd surprised if it would be reliable.