Looking through the docs n’ stuff, this is what I found:

• Updating Guide. Just basic steps, similar to what I explained above; but with commands to run.
• Backing up and restoring
• 2.0.0 Change Log. Unfortunately they don’t include any notes about how to upgrade

I wasn’t able to find any additional instructions on how to update other than the expected generic steps (docker pull or pip install -r requirements.txt). So my guess at this point is that they have scripts built in to check the version and run upgrade scripts as needed

I haven’t gone through your specific case, but generally what I do when doing a major update with potentially breaking changes:

• Read the upgrade guides, if they have them. Some devs will put them out if they know their users will encounter issues when upgrading. If they don’t have an upgrade guide, there might be some in the change logs. Going from 1.17.1 to (assuming) 2.x.y, check the change logs at 2.0.0.
• Backup everything. I’d recommend doing this on a regular basis anyway.
• (If you’re running it in a docker container) Setup a second instance, restore the backup, then run the upgrade. You’ll be able to check to see if it breaks at all. If it works, you can just destroy the old one and use the new one
• (if you’re not running it in a container) with the backup, try upgrading. If it breaks, you should be able to uninstall & reinstall the old version, then restore the backup

I usually only keep documents and media. Programs can be redownloaded and reinstalled (and it might be better to reinstall them in case you move to a new OS anyway to ensure compatibility).

For docker specifically, only keep stuff that’s specific for your instance; which you normally setup as an external volume anyway. Docker is designed such that you should be able to nuke the container, and all persistent data is restored via an external volume on the host. If you’re not doing that, you should immediately go and set that up now (to get the data out safely, setup a volume connection such that the container path is new - that way you don’t accidentally destroy what’s there, copy the stuff you need out, then readjust the path so it’s correct)