I have another idea to throw out that might work in your case. If the server is small and does not have many users, you might consider accessing all the libraries and data using the FUSE extension so that you can then re-sync (or upload) the contents in a new server. From the Manual:
Files in the seafile system are split to blocks, which means what are stored on your seafile server are not complete files, but blocks. This design faciliates effective data deduplication.
However, administrators sometimes want to access the files directly on the server. You can use seaf-fuse to do this.
Seaf-fuseis an implementation of the FUSE virtual filesystem. In a word, it mounts all the seafile files to a folder (which is called the ‘’‘mount point’‘’), so that you can access all the files managed by seafile server, just as you access a normal folder on your server.
Essentially you can backup all the data first and then reintroduce it into a fresh new server using the same accounts (and libraries) that exist on the old. Of course this is practically impossible with a large busy server with many encrypted libraries but it might fit in some cases, maybe even yours.
Interesting?