Hello all
Go to https://www.asus.com, then under promotions, ProArt monitor warranty extension, sign up. You then have to answer a few questions and upload a copy of your invoice and a picture of the Asus serial number label. The whole thing looks like an event, but it really is. Shortly after submitting the form, I received an email from Marketing@asus.com confirming that the warranty had been extended to 5 years.

Same for me. I would also be interested to know how to activate the warranty extension. The relevant link from digitec only leads to a meaningless index page from ASUS, where nothing can be found on the subject of warranty extension...