I actually asked Sean way back if he did "upgrades" and he didn't. So
technically you'll have to buy 2.0 fresh at the full price. Whenever
you find Sean selling them on eBay of course.
I had a 1.0 myself and sold it in the past when I got 2.0. Actually
regreting that. So if you are interested in selling your 1.0, let me
know
(I'll next see Sean in early July and if you still haven't got a 2.0
multicart by then, I'll ask him if he's got any spare for me to have)