[arm-allstar] Updating Python3 to later version ?

[Gerry Filby]

Hi Folks,

The most recent Pi image has python 3.5.1 installed - how do I bring 
that up to date ? ... well ... more up to date, at least 3.7 although 
3.9 would be great.

Appreciate any help you can offer ...

Best,
Gerry.
W6WNG