Had trouble upgrading the skyjake.fi Mastodon instance to 3.5.1 (from 3.4.6). The PostgreSQL database must be manually migrated from version 9 to 14, and the provided steps were not working.
Turns out that something was breaking when piping the dumped SQL data to the new db image. The solution was to instead use the `-f` option with psql, reading the dumped SQL data from a file inside a mounted Docker volume.
Next job: Upgrade the server to a new Ubuntu LTS version at some point...
skyjake's personal Mastodon instance