Is there any option to reset the trial on a major update? I want to move my application from version 2.x to 3.x

In order to reset the trial on a new protected application, you have to change the "Trial Unique Key" (in the Software panel in the Winlicense GUI). The "Trial Unique Key" is an identifier to indicate where the trial will be stored in the system for the protected application.

If you re-protect your application and you don't change the "Trial Unique Key" the new protected version will continue the trial at the same point as your previous protected application. Or if you have two applications protected with the same "Trial Unique Key" they will both expire at the same time (when one expires the other one will expire too)

If you change the "Trial Unique Key" for your new protected application or for a secondary application that you protect, it will have a new location to store the trial information, so it has a fresh trial. That means that if you re-protect your application again with a different Trial Unique Key it has the same effect as a trial reset.