One customer gave feedback that he failed to add key to VAG 5C/5D, the following is his operation process:
1. Used USB cable to connect Keydiy KD-X4 key programmer and a computer
2. Installed KD App on WIN11
3. Updated KD-X4 firmware to the newest version
4. Selected immobilizer programming- Volkswagen-selected by type-5C/5D immobilizer system
5. Started the process, appeared error message “login reminder” after starting 
Cardiagtool.co.uk engineer replied:
The Volkswagen MQB49 (5C/5D) add key functionality has not yet been released for Keydiy PC/Windows software platform.
Please switch to Keydiy mobile app on an Android device.
KEYDIY KD-MP and PC software will release the MQB49 5C/5D function afterwards.