Edit: Due to a Di2 update you can now allocate shift buttons to control Garmin screen actions such as changing pages, starting timers, map screen activation etc, with an Ultegra 6870 setup that does not have the buttons under the hoods.
This video covers replacing the older D-Fly SM-EWW01 Ant+ transmitter with the new EW-WU101 transmitter to enable Bluetooth and synchronous shifting. The new EW-WU101 is not compatible with the older Di2 SM-BTR2 battery and thus installation of the BT-DN110 is also required.
