I originally created a ticket in Merchant Onboarding but I realize now that probably wasn't the right place for it.
My understanding was that if we updated our app and transitioned it from free to paid, that existing users would be notified of the change, and then be prompted to update.
I had an existing user send me screenshots of his experience, he does see a prompt to update now but when he tries to update he get's an error message: "The operation could not be completed. (ConnectIQ.NetworkManagerError error 4.)"
I'm not sure if this is related to the fact that he hasn't setup Garmin Pay yet, if that's the case the error message should be improved.