If you have purchased your license for WYSIWYG Web Builder via http://www.wysiwygwebbuilder.com after June 21, 2020 then you qualify for a free upgrade.
Enter the serial number you've received for WYSIWYG Web Builder 15.x and click the Submit button.
If your serial number qualifies for a free update then your new serial number will be displayed within a few seconds.
Note that if you already have a license for version 16.x, the you do not need a new serial number!
If you bought the license before June 21, 2020 then you can make use of our (limited) discount offer:
http://www.wysiwygwebbuilder.com/upgrade.html