In the event of migrating your old vCenter Server to a new version (or from Windows to the appliance), it may become necessary to first clear out old historical data. Not only will this speed up the migration process considerably, it will also prevent certain issues which may block the migration from completing successfully.
VMWare provided a KB with database scripts which allow you to selectively purge historical data and decreasing the database size: KB 2110031.
The Barracuda VPN Client does not work properly on macOS Mojave: after connecting the VPN, the UI crashes and restarting it immediately makes it crash again. The VPN tunnel itself does work, but other than manually killing the process (kill -9), it is not possible to terminate the tunnel (other than rebooting of course).
An updated version of the client, Barracuda VPN Client 220.127.116.11 for macOS is available which resolves these issues.