My upgrade went fine, but I want to mention one thing that might confuse a new user doing his/her first old version-to- new version upgrade.
Everyone that has done "new version" upgrades knows about the "countdown timer" for the automatic media import feature. A feature you either love or hate.
For Upgraders: When you are upgrading a client, there is no need to auto-import anything on the client's drives as your media is all on the server, so JRiver gives you about 60 seconds to turn off (cancel) the auto-import.
But if your (previous MC version) client machine is set to start in Theater View mode (a typical view for a client), as soon as the upgrade completes the client machine switches to Theater View. The problem with this is that the auto-import countdown timer is still running, but hidden now - and if you don't know about this, and/or are not fast enough to switch back to Standard View, the auto-import will occur.
Having auto-import run on the client is not the worst thing that can happen, but it would be better, IMO, if it was not automatic (I think a popup asking if you want to run it would be better) or perhaps the install should always complete on the Standard View page.
This post is just a warning for new Users, and a suggestion to JRiver team to consider for improvement of future versions.