An answer is forthcoming. Since Lensfun support was added to SILKYPIX, it hasn't always gotten updates to the Lensfun database to bring it up to the most current version. That may be why it isn't appearing as an option but we are following up....
Please create only one user account per person. The only exception is if you need a separate organization account; organizational accounts need to use your organization domain.
Registering? We send an activation email. Your account is not activated until you activate it using the email link.
Go to Support Center >FAQ for more information.