This new release involves some hugely important refactoring -- and lots of it. There have been 3.5 times as many code commits since version 1.5.1 (564) as there were between 1.4.0 and 1.5.0 (158).

So, you ask, why not call this wonderful overhaul Wagn 1.6?

See http://www.wagn.org/Wagn_1.5+2 to find out.