Shimano's latest external mount battery is the E8016. A 630Wh battery that offers a substantial jump in range over its next largest battery the E8010 504Wh battery.
Bad news, the E8016 is a large battery that will not work on the older BM-E8010 battery mounts. A new battery mount, the BM-E8016 is required.
Good news, the new BM-E8016 battery mount will accommodate the older E8010 and E8014 battery. So at least you can use your old batteries but you will have to by the new BM-8016 battery mount.
Bad news, the E8016 is a large battery that will not work on the older BM-E8010 battery mounts. A new battery mount, the BM-E8016 is required.
Good news, the new BM-E8016 battery mount will accommodate the older E8010 and E8014 battery. So at least you can use your old batteries but you will have to by the new BM-8016 battery mount.
My Correspondence with Shimano
My Question - Can the down tube battery mount for the E8010 be used for the new E8016 battery
Shimano's Answer - Hi Mark. The New BT-E8016, does require a new battery mount BM-E8016, and will not work with the BM-8010 mounts. I hope this information helps. All the best.
My Question - One last question (for now). Will the new BM-E8016 mounts work with the older E8010 battery?
Shimano's Answer - Hi Mark. Yes the BT-E8010 and the BT-E8014 will work on the BM-E8016 mount. All the best.