I just completed this upgrade and the system seems to work, but there were a couple of issues which I can't quickly find logged here already.
1 An upgrade script error
See this image.
I'd guess that's saying that the 315->327 upgrade worked without errors, but
the 327->339 one throws that error...
Without looking at the schema, the name suggests it may be a user defined type. Those are a pain to upgrade with scripts - you can't change the type without zapping everything which uses it first, they're just nasty. I did not try to debug this; not sure if
I need what it does or not.
2 Permissions Error
This is weird... On re-starting the server all the images were throwing 404 errors. I guessed it may be permissions and just set "everyone" "can do anything" on all of them, which fixed it. Still, not had that before with this.