You have update to 4.2 BUT did you upgrade your template to 4.2. If you just restore your templates from 4.1, your templates are probably still running on r4.1 (that’s why everything work like old appvm).
I did the same error.
Check with cat /etc/yum.repo.d/qubes-r4.repo for fedora’s template and with cat/etc/apt/sources.list.d/qubes-r4.list for debian’s template to see if repositories have been updated to 4.2. If it is not the case, look at there: [guide] how-to setup a sys-dns qube - #68 by Tezeria and use the script that @DVM has linked. It’s very easy to use
