All existing Reference 3 users can upgrade to Reference 4 by going to our upgrade page and checking what kind of upgrade options are available to the user by entering all of the Reference 3 activation codes they own.
IMPORTANT! Your existing Reference 3 activation codes will still be usable for Reference 3 but won't be available for registering another upgrade.
If you are eligible for a free upgrade, your Reference 4 code will be emailed to you right away. If you are eligible for a paid upgrade, you'll need to purchase the upgrade. This will send you an upgrade code to your email address, which then must be entered in the same page you requested the upgrade from in order to get your new Reference 4 activation code. This will be also delivered to your email address.