You update manually via SSH. It's a bit more tedious than a package manager but not too bad. It took me a while to wrap my head around their file layout and how they do things, but I have it figured out now and updating takes a couple minutes. I can have two SSH terminals open on the same machine and by the time the first one completes `apt-get update && apt-get -y upgrade` I'm nearly done with the Seafile update. I really don't like adding third-party PPAs so I'll probably stick with this method for a while even if someone manages to package it up.