You want to update the operating system, not the Karaf container. SSH to to the machine, not the console. If it looks like this when you log in you are in the wrong place.
__ _____ ____
____ ____ ___ ____ / / / / | / __ )
/ __ \/ __ \/ _ \/ __ \/ /_/ / /| | / __ |
/ /_/ / /_/ / __/ / / / __ / ___ |/ /_/ /
\____/ .___/\___/_/ /_/_/ /_/_/ |_/_____/
Hit '<tab>' for a list of available commands
and '[cmd] --help' for help on a specific command.
Hit '<ctrl-d>' or type 'system:shutdown' or 'logout' to shutdown openHAB.
If you installed using openHABian, the username will be openHABian, I’m not sure what the default password is. From there you can run sudo openhabian-config. When it asks for the password, it’s the same as the password that you logged in with.
Many thanks. However, no combination of username or password will let me in via Putty. I can see that I’m in the wrong place when I use the terminal (is that what’s it’s called on Linux?) on the Pi itself. I just want to get to the screen above so I can run the update but I have absolutely no idea how to get there. What am I missing?