This should work on most APC UPS, but it is actually tested just on BE700G-GR aka APC Power-Saving Back-UPS ES 8 Outlet 700VA 230V CEE 7/7)

Update BATTDATE

There is no magic here, you need to run apctest and go to the View/Change battery date menu.

(You might need to stop apcupsd first as it cannot run in parallel with apctest)

You can find the date on the bottom of the new battery (month and year).