A large sticker on the front of the X-Vive states you can register with them for a 4 year warranty extension. I did so, but there's 2 stickers on the box. I used an incorrect S/N label which appears to be Thomann's own, and XVive's website stated that they had received the registration. I thought, all good, I'll bin the box. Then a few days later I got a rejection email.
It's taken me until now, 3 months from original purchase to find the box. I went to register again with the second serial number and Xvive rejected it because it's out of the 45 day period. I explained the circumstances, and received a cold rejection - no token of goodwill, no exception made for a genuine customer.
I won't be buying an Xvive product again. And our Drummer's U4 pack had a switch failure and had to be returned. Shocking company, shocking quality. Avoid.