Despite having done lots of reading, some things have slipped past me.
Having updated the firmware when I first got the MP, I found myself getting a Firmware doesn’t match error on occasions. I updated the firmware again, and didn’t see the message for a number of weeks. When I did I vaguely remembered about an issue with internet access on phones and ignored it.
Saw it again yesterday and decided to sort it out. Of course, what I now realise is that the messages from the GO4 app are a bit terse, and what it really was telling me was that I had 3 batteries and only two had the right code in them!
Now I’ve got to grips with the DJI Assistant 2 and all three batteries are sorted.