2FA key for authentication the device: Changing size, what happen?

[Michael Beneke]

Dear community. 

We want to change the key  size which is generated with the QR code for authentication the devive for the 2FA.

Change from 8 to 16.

To be sure: Is there any issue with existing accounts?

Unlucky my search for this was not successfully.

Thanks for your answers.

Kind regards

Michael