interoperability of elicenser versions with single dongle

I keep seeing things that say you should always update the eLicenser software to the latest version. But, I’m running two ancient OS X versions, 10.5 and 10.6, and the latest eLicenser that will run on 10.6 is much more recent. I want to be able to keep moving the dongle between the machines, using older versions on the older machine. Is there a point at which this doesn’t work? should I fear getting the relatively recent update that still supports 10.6?

I’m not a Mac user but I use a dongle between really old machines (Win/XP Sp2 ) and a newer Win7/64 one with no problems as long as I update the eLicencer on the old machines.

The old computers are from around 2001 so it’s a dinosaur in computer age but runs flawlessly ( never been online )

I haven’t a clue if this is relevant to a Mac, so I apologize in advance if it isn’t