There have been new mods released just a couple of days ago as well as styles. Have you not looked at the Resource Manager accessible by clicking Resources at the top. As far as development with the core software I think the devs were waiting (possibly still developing secretly) until the end of the court battle with Internet Brands. Which could end today (if settlement talks go well) or in a couple of months. We will just have to wait and see as far as that goes. There are still people actively making addons and styles for xenForo.