sorry for disturbing, I've just got my a4+ today, I've checked in the overview, I see it's as below:

A4+
Hw Version    G19
DNA    0x1488076484c2c1
MAC Addr    50:6c:be:08:76:9f
Build Date    Wed Nov 22 09:30:31 CST 2017

May I know which firmware is the most stable one? or if there is any other newer and stable firmware available please? should I upgrade it?. Thanks.