"Perpetual updates" - well, they did it, but also had some hardware changes. It is called M9 and you can get it from your friendly Leica dealer.
Now, seriously, if Leica would throw in a software update for M8/M8.2 users with more than big bug fixes, that would be a major surprise and something that has not been done until now in this business I think. Even if it sounds like simple, it is not the case, and if they have tried to optimize cost and are on the limit with RAM/ROM in the chip, it simply isn't possible. Even if it was, it does cost money, and that amount would go into something not earning money, since you already payed for your M8. Leica are at this time the only player in digital RF. If more players come in, with a Leica-M mount, they would have a harder time in this small market than the other (DSLR) manufacturers, since those have all their own mounts, unlike a unified M-mount market of DRF. But, as much as I would like to see some options, I don't think this will happen soon.