I had a chance to try JP on a Samsung Galaxy Tab and found that the progress bar wasn’t extending properly across the larger screen. I fixed this, such that any screen size should work properly. I’ve also built the program using the Android 2.3 (Gingerbread) SDK and run it within a 2.3 emulator without any problems. I haven’t had a chance to try it on the new Nexus S with 2.3, but it should work just fine.
The only new feature in 4.1.0 is for JPP. You can now select tracks from the “Create playlists” function of the app and then, when you use the “Edit playlists” function, you will be asked if you wish to insert these tracks into the playlist(s) being edited. Thus, you can add tracks to existing playlists, rather than just being restricted to editing and combining playlists.