So I’ve decided to re-visit Avast, and now see that they’re calling their product “Avast One”. That’s fine… I installed it and got it working just fine.
However, I cannot find where in “Avast One” one can create a “Rescue disk” bootable USB drive for running an offline scan? You could do this in the previous version, even the free version.
https://support.avast.com/en-us/article/Antivirus-Rescue-Disk-scan/#pc
You can still do it but not in AvastOne.
Doesn’t AvastOne replace the old antivirus app?
No it isn’t a replacement Avast One has a different feature set to Avast Antivirus.
There are some things in Avast One that aren’t in Avast Antivirus and vice versa.
For me the biggest reason not to go to Avast One is it doesn’t have the configurability of Avast Antivirus.
Are you sure?
When you pull up Avast’s product comparison table, they only mention the various flavors of AvastOne:
https://www.avast.com/en-us/compare-antivirus#pc
So Avast themselves are downplaying the old software. In fact, when you go to try to find/download the old Avast AV, they really try hard to steer you to Avast One.
Then other places consider it a replacement. From TechRadar :
“Avast One (opens in new tab) is the new name for Avast’s revamped and redesigned consumer security range, and combines antivirus (opens in new tab), VPN (opens in new tab), privacy and security tools to keep you safe online.”
From this conversation over at Reddit:
“Avast One is a noticeable upgrade over Avast Antivirus Free, with much stronger malware protection, far fewer popups and works without an account.”
From PCMag:
“The Avast One product line is clearly the wave of the future.”
Yes I’m sure, it has been mentioned many times on the forums, but I haven’t got a specific link.
I guess they don’t visit the forums 
Though it wouldn’t surprise me if ultimately it would go to one product range/family, Avast One (Paid version) and Avast Essentials (Free version)