AFAIK licenses are not bound to a specific host, so if you uninstall Fusion on the old MAC you can use the license on the new one.
While trying to find that in writing on the VMware web site, I found an interesting information, that I wasn't aware of yet.
Can I install Fusion 11.x on more than one Mac?
Personal users require only one license to install on all Macs, but business or educational institutions require one license per Mac.
Careful with "Time Machine" to a new machine bit.
That works OK for most things, but is not a reliable way to transfer your VMs!
For the why, please see this KB article: https://kb.vmware.com/kb/1013628
So the recommendation is to manually follow these steps:
- shut down (not suspend) the VM
- commit any snapshots you still might have
- close VMware Fusion so that it is no longer running
- copy the whole VM bundle to an external disk
- disconnect that disk, then upgrade to macOS Mojave
- after copying the VM to the new computer, use File -> Open to open the VM at the new computer
- When VMware Fusion asks if you copied it or moved it, select "Moved It" as otherwise you will have to re-activate windows VMs because they will end up getting a new set of hardware identifiers.
Of course you are also welcome to use my backup program (see my signature) for this purpose, but the above works fine.
Hope this helps
Wil| Author of Vimalin. The virtual machine Backup app for VMware Desktop Products
| Vimalin : Automated backups for VMware Fusion and VMware Workstation Professional
| More info at https://www.vimalin.com
| Twitter @wilva
| VMware Wiki at http://www.vi-toolkit.com