Does what it's supposed to...but the real joy of the new DN110 (vs BTN2) is the ability to allow the slimmer D-Fly replacement Di2 transmitter AND the ability to support syncroshift on Ultegra Di2 (as of 32017) with firmware upgrades (you are regularly upgrading your firmware, right?).
I replaced my older BTN2. I was upgrading my derailer and I wanted the features on the e-tube app so figured now was the time. Straightforward unplug and plug. It is not clearly stated so I was confused if the new battery alone support blue tooth or I needed to add the EW-WU111. This is not the case. The BT-DN110 WILL pair with your phone and you can use the etube app. This DOES NOT require the EW-WU111.
Also, the new batteryderailer combo supports synchro shift which I unexpectedly like very much.
Cant do synchro shift without this battery, and its worth the upgrade just to get synchro shift. I'm not a lazy shifter but it is convenient in a race to not have to think about the gearingcross chaining as you meet hills. Just shift!