Hi Robin and welcome to Avast forums.

It is the same. You have to open Avast > Settings > Active Protection > Secure DNS > On/Off

https://www.avast.com/en-us/faq.php?q=Secure+DNS#searchForm

If you do not want it anymore, and you want to deactivate it completely.

Start > Control Panel > Programs > Programs & Features > uninstall a program > Select avast! and click " Uninstall/Change ". Choose “Change” and Continue. Untick Secure DNS.