im considering replacing my pi 3B with a newer PI 4(My pi died last night). Running the latest OctoPrint release version, and have allot of plug ins and setting configured. would i be able to simply swap the SD Card to the new PI 4, or would i be better off just replacing it with another PI 3B and using the same card and be back up and running much quicker?
Well it depends if your old pi was running octopi 0.17 or if the image was updated via
sudo apt update && sudo apt -y upgrade.
If the image got no pi 4 support you can update it with another pi.
You could also backup your octoprint settings by hand
You have to mount the sd card on a linux based system or use a tool like this on a windows based pc for the by hand backup. There are some tools with free read only modes which should be enough for this use case.
To this, I'd add that the
/boot/config.txt file for a Pi 4B now includes sections (at the bottom, usually). It might be worth reviewing these changes.
Typically, this allows you to move the microSD back/forth between a 3B and 4B and have it do slightly different things. In my own case, I want to use a particular CPU/GPU memory sharing on the 3B but something more generous to GPU on the 4B.