According to the web site version 3.6.4 is the "last release of
EazyDraw version 3, for users who have not purchased Version 4
upgrade. This version does not run on Lion (OS X 10.7)".
https://www.eazydraw.com/support.htm
Having only purchased EasyDraw in February with no suggestion that it
wouldn't be compatible with Lion (and also recommended it to several
other people) I'm rather disappointed to find I'm expected to pay $35
for an upgrade just six months later. I appreciate that you're
allowing a two-year 'grace' period but it seems a rather convoluted
alternative to simply offering a free upgrade to recent purchasers.
(And won't there most likely have been another paid-for upgrade within
those two years?)