This means that existing VM's really move.
Perhaps the most noticeable feature is that Parallels Desktop 14 is 35% faster than previous versions and it was immediately noticeable, too. Parallels Desktop 14 fully supports Mojave's Dark Mode, one of macOS' most anticipated pieces of eye candy. Over and above the mandate, if you will, there are a few benefits to the new software. Existing Parallels users MUST upgrade if they move to macOS Mojave. The new OS will have features that will impair the functionality of or outright prevent the software from running. A new macOS version will always require an update to key utilities like Parallels Desktop.
The biggest is that version 13.x won't run on macOS Mojave. There are a few key reasons to upgrade to Parallels 14 from an earlier version.