I did that. And it doesn't allow me to add manually which software I want specific rules to. It only shows up once I've booted the software, only then I could modify it. But as I discovered today, it did erase all of my previous custom rules. I had certain software that I locked out of the internet because they have a tendency not to let me decide when to update, and I was surprised when one of them did update automatically.
Apparently, the latest update implemented a sort "general rule" that was different than the ones I had customized previously. So now I have to set my default action to "ask me" first, and redo my settings by opening up my softwares one by one just so it would even show up on the firewall list. Highly inconvenient. Avast should've just given us the option of keeping our own custom settings.
An example would be like Nvidia drivers, where every update gives us the option of either keeping our previous settings or starting from scratch.