My trusty Di2 battery has finally given up the ghost and whilst I'm mildly annoyed at the cost of replacing it (I was hoping they'd have come down in price!) I'm now faced with a choice. Do I just replace it, like for like (SM-BTR2) or do I buy the new BT-DN 110? More importantly, I've read on an Amazon review that I may have to update the battery software if I buy the DN110 or can I just plug it into my 6870 Di2 set? I don't have any wireless device on my set up. Thanks!