Unable to upgrade GNS3 VM to 2.2.56.1

[ubidev]

Hi I have a classroom lab with 10 GNS3 Server Hyper-V VMs.
I've been using these, hassle free for many years, upgrading without issues every time there is e a new version.

This time is different though as I'm getting the following error on all vms that prevents the upgrade from completing:

Any help on this otherwise very fine project would be appreciated as I have a new group of students tomorrow

Thanks in advance for your time :)

[ubidev]

As a side note, I've upgraded all clients to 2.2.56.1 and besides the usual mismatched version warming, everything I need works fine !

[grossmj]

This is because Python 3.8 support has been dropped.

What Linux version do you run in your VMs?

[ubidev]

In the shell it reports 3.6.9 from memory. I thought all the GNS3 server dependencies were upgraded during the upgrade process. Since I don't know if the project uses the OS python version or a version installed in a venv or elsewhere, what commands should I run to upgrade properly to your experience?