There are two products on Amazon for model A1231:
Only the new one is still being sold by Anker (ASIN:B07XNX88G3), but I’d really like to know what was upgraded. The old one has model number AK-A1231011. Is the upgraded one AK-A1231012? Was something fixed or added? Even a general answer would be helpful.
Couldn’t really find anything different about it 
For stuff like this it’s usually just minor things like updating USB standards and drivers and stuff like that.
To be quite honest we don’t really need to worry about it. Just always get the latest version and you’ll be good
Sometimes it is a compliance change. Short of disassembly or a direct quote from Anker. Most likely won’t ever know.