Successful update to the latest pi-hole just now. I was holding off because of a few reported issues, all went smoothly by following this poster's advice:
https://discourse.pi-hole.net/t/apt-get-error-on-update/49569/5
@voltronic
Thanks for this...
I will do a clean install, probably next week.
^ Note that this only updates the OS release info; it doesn't actually update the OS. The Pi foundation recommends against doing an in-place update; you are safer doing a clean install.