Hi,
You’ll have to do some intermediate steps, the manual states you should be at least on 8.0.x to migrate to docker. This could help you:
- Migrate from non-docker deployment - Seafile Admin Manual
- Outline - Seafile Admin Manual
- Upgrading (not moving to a new server) pro-server 7.1.7 (running on Debian 10.13) to latest?
Can’t help much more than that, but good luck!