Got a Qatar biz upgrade offer, can you pay it fully with Avios?

Got an email from Qatar with a discounted upgrade from economy to business. At checkout I’m seeing the cash + Avios slider, but I’d have to transfer points in first and I can’t tell what the actual Avios rate is… or if you can even pay the whole thing in Avios instead of part cash.

Anyone know how these upgrade offers work on the Avios side