Seafile 6.2.7 > 6.3.9 /media/assets/scripts/app/main.js not found

I just upgraded my seafile server.
While the backend works (files are syncing), the seahub page doesn’t work.
Seahub starts, but when I open the page I only see the loading circle.
Opening the Chrome dev tools, the console says “/media/assets/scripts/app/main.js net::ERR_ABORTED 404 (Not Found)”.

And indeed there is no /app folder at all in /seafile-server-latest/seahub/media/assets/scripts.
What’s wrong here?

try this

Upgrading to .13 solved this problem