Well I missed the memo about staying on buster, and migrated to bullseye (I have a few pi's so have done this with all of them) however this upgrade went a bit wonky as I'm sure some of you can imagine.
I followed some info here: PiOS Bullseye killed Octoprint - #10 by sammytrailor
And got octoprint running again with the reclone, I can tell it's running because I use a display with octoscreen and it was crashing before following the steps noted in a post in the topic linked above, but after running these:
mv ~/oprint ~/oprint.backup python3 -m venv ~/oprint ~/oprint/bin/pip install octoprint
Octoprint appears to be running again.
Now though, even after using a posted / good config from the same thread for haproxy I am met with the nginx splash when trying to load octoprint:
The same splash is displayed for using
octopi.local, and if I try the IP:PORT method to access the webUI too.
You can download this in OctoPrint's System Information dialog ... no bundle, no support!)
OctoPrint version, OctoPi version, printer, firmware, browser, operating system, ... as much data as possible
Latest octoprint, upgraded bullseye octopi image.