Hi Ivo,
Happy new year. We don't really "do" version numbers… sorry.
If you still have the virtual machine, you can do
cd ztree-unleashed
git rev-parse --short HEAD
in the terminal to find out the latest git commit associated with the virtual machine.
And here is a full list of commits:
https://gitlab.com/cler1/ztree-unleashed/-/commits/master/?ref_type=HEADS
Best,
Max