With all the various things in L5, and what I read, I should heed the posts and pay more attention to ‘it’, whatever ‘it’ is.
To save trudging through more wrong answers, just what is “Byzantium” and do I have it, if not is it a good idea to install it? Or if I have it, should I see a doctor? 
Byzantium is PureOS 10, which is based off of Debian 11. It is the default version installed on Purism devices, except for the Librem 11, right now. Crimson is the next version of PureOS that is still being worked on and is based on Debian 12, which will soon replace Byzantium.
To know what version of PureOS you are running, type this at the Terminal:
hostnamectl
You should see something like this at the end of the output:
Operating System:
PureOS 10 (Byzantium)
Kernel: Linux 6.3.0-1-librem5
Architecture: arm64
Thanks - I tried to find what would be used in Terminal but didn’t ue th right words I guess.
Many thanks
~s
This information is also in the Settings app, under “About”
lsb_release -c
