It were busy few weeks, but now it's finally all over, and I had some time to finish the version 4 PCB. It turned out to be much simpler than anticipated — the difficult part was figuring out which pins I can use, and that I did already previously. So I ended up with a simple board like this:

I have to say that I forgot how much using a ready development board simplifies the design. It's basically just connecting things together, and a little bit of more complexity around the power.