Sorry for being late.
Last year I had the same issue with my Puck after battery replacement.
Mares Puck can handle 2021+. The bug: It's not possible to set year to 2021+. Shame on the software developer
.
This workaround works very well for me and tooks not more than 5 Minutes:
Set the 31st of December, 23:59 h, of the newest year you can choose. (think it was 2019 or 2020, not sure).
Now you have one minute to celebrate New Year's Eve with your Puck. Year will count up.
Change the date from 1st January to 31st December, 23:59 h. Be careful, don't touch/set the year. Otherwise you have to start from begining.
Again one minute New Year's Eve with your Puck.
Repeat until you reached the actual year and set today's day and month. That's it.
Hope this helps to increase the life cycle of some Pucks. (or other Mares computers with the same bug)
Cheers
M.