"A PostgreSQL Docker container that automatically upgrades your database"

Still uses "upgrade", but highlights the fact that you're changing the artifact and not just the software.

Thanks, that sounds good. Looks like I can't edit the title for this any more now though.

I'll email the HN mods and ask them if they can do it. :)

Title changed. :)

Also copied that wording to the GitHub repo page, Docker Hub page, and will probably use it everywhere else that needs a description too. :D