I played around with this new version tonight and I had a few things happen.
First time I tried RC1 the game loaded up fine with my previous settings from version 6. When I turned off the system and restarted it would not load a game. Not from a cartridge or from a rom file, it would just freeze. I was able to get everything up and running by deleting the database settings files.
I tested overscan settings on a CRT using an HDMI to S-Video adapter and everything was there was working well with that.
I tried paddle games from the db9 port and was unable to get them to respond with actual paddles or the ranger controller. I was able to fix this in previous versions by going to the basic settings screen or resetting to default configurations, but was unable to ever get the paddles to work. I did however get the paddles to work using the 2600-daptor.