Is BMS 13 worth the risk?

I have a 13.5 kWh AIO battery installation running with BMS 12. Unfortunately when not daily using its full charge / discharge cycle it is prone to suffer with up to 5% per day drift in SOC reading. I have on several occasions experienced a 40% "realignment" of the SOC reading. When GE stopped trading (which was also when I found out that BMS 13 was available) someone posted a comment saying "Unless there is a pressing need to upgrade, don't. As there is no backup if anything goes wrong.
Comments please on :-
Does BMS 13 cure the SOC drifting?
Is the download still available?
Has anyone had problems with installing?
What backup is now available?

No issues here with 13.
Upgrade was easy, but I’m wired not WiFi and have never really had any issues with firmware updates since the start. Was fully updated prior to administration so not done any updates recently.

Still get SOC drift in summer if the battery spends a couple of weeks sitting in the 50-100% range, and typically manifests with 40% ish to empty quite quickly.

With the AIO if you want to have accurate SOC you have to empty it down to 4% at least once a week and then charge back to 100%. That's what I do and I never have SOC issues anymore.

BMS 13 won't cure soc drift. It is clear from others who are daily importing & exporting from top to bottom or are weekly doing a soft or hard calibration, that the AIO knows where it is and things run smoothly. I don't and regularily get the drop off. Tonight I need to do a top up. If there was an "off the shelf" product to buy that had this HA on that was just plug and play, I would probably invest. It would have to be fool proof and easy to set up for non techies. I could then drain battery into car and let it auto refil on a regular basis.