huh, I don't remember when that capability came in, but I didn't really notice until until I got my tablet, so I can say it's at least a few years old, but not sure how much older. (the "brush dynamics" option is on each tool's options menu, not under the brushes menu, if I was unclear about that.)

...I have just checked and I thought I was up-to-date, but my version's two years old already actually. Um. So maybe I should fix that too before I start giving advice.