OctoPrint is platform agnostic and can run basically anywhere where Python 2.7 or 3.7+ is available. It officially supports Linux, Windows, MacOS X and FreeBSD and is actively tested on Linux and Windows.
OctoPrint is most commonly run on Raspberry Pis running OctoPi, the Linux/Raspbian-based prebuilt image ready-made for OctoPrint. However, not all models of the Raspberry Pi are officially supported. We've observed significant performance issues, even leading to print failures, with the Raspberry Pi Zero/Zero W, which is why these models are not and never have been officially supported by the OctoPrint project, contrary to what you might have read elsewhere on the internet.
The officially recommended Raspberry Pi models to run OctoPrint (and OctoPi) on are the Raspberry Pi 3, 3+ and 4. All other models are not to be considered supported and you use them at your own risk, even though OctoPi does boot on them.
If you want to migrate your OctoPrint installation off an unsupported model and onto a RPi3 or higher, you should be able to simply move the SD card into the better model. Alternatively, make a backup via OctoPrint's built-in function for that, flash a fresh image to the SD card and restore the backup on the better model.