There is one thing that I've found that may need some looking into.
User and document permissions. I can see there is now a selector for mgr and web. All my exisitng permissions have been migrated to 'mgr' but that means that frontend is accessible unless the document is a resource for all.
Maybe all permissions should be duplicated for 'web' during installation?
This is on an existing site which was v3.1.10.