Ver. 4.0.1

■ Changes
Security performance for wireless communications between the shifter and rear derailleur has been improved.
Click here to view FAQs for more information. https://bike.shimano.com/faq/DI20A#D-7030
*The firmware for both the shifter and rear derailleur must be updated for proper operation of the Di2 system.
* Wireless firmware update is not available for this product.
Update the firmware over a wired connection or contact your place of purchase or a distributor.
■ Others
General bug fixes.

Ver. 4.0.0

Firmware released.