if i bought this product here, do i have to pay for every upgrade when i buy it again?
no, you don't have to pay multiple times , future upgrades are free for those who already purchased it ; some days ago a bug happened, but now is fixed and the system lets you select every version for download :)
not. this is not if you click on the link directly. only through the library ... which in turn is like a surprise for everyone who knows only German.