I successfully installed a freshly downloaded virtual instance a few days ago, running in VirtualBox on Windows 10. Seems to be working fine. Noticed that under 'Statistics' on the home page is was dated April 2016. Configured with a key for replication, ran 'bin/replicate start' and now the Statistics page update is 05/22/16. Interestingly the mirror http://musicbrainz-mirror.eu:5000/ shows the same 05/22/16 date.
It seems the database schema changed on 05/23/16 (https://blog.musicbrainz.org/2016/05/25/schema-change-release-2016-05-23-with-upgrade-instructions/) but the virtual machine available for download is dated 2015-08-06 on http://musicbrainz.org/doc/MusicBrainz_Server/Setup
So automatic updating stops at 5/22 with the current virtual machine. Seems to make sense but where is the latest virtual machine build, or is that left to the user to build from the GitHub repository?