1. Backup your existing Avast Settings. These settings can be applied after an update, whichever one you choose to do.
2. Do a system backup image as previously mentioned.
Then you can pretty much do what you like. The Program update was released on 09 October 2018, so 3 weeks is a very long time when you are talking about a program update every month.
Considering there hundreds of millions of Avast users, do you not expect to see some issues reported in a support forum.