Although restoring R3.2 AppVMs to R4.0 generally works with no problem, there are additional steps that need to be performed when doing the same with Templates and Standalone VMs.
6. On the restored template's terminal, `cd` into the `QubesIncoming` subfolder that contains the files you copied over from the known good R4.0 template, then in `su` mode:
~~~
cp qubes-r4.repo /etc/yum.repos.d/
rm /etc/yum.repos.d/qubes-r3.repo
rpm --import RPM-GPG-KEY-qubes-4-*
dnf update
### You will receive an error about qubes-core-agent transaction failed, so continue with: