You can have “Bar Extender (Checkmk 2.0) 1.0.3” and “Bar Extender (Checkmk 1.6) 1.0.4”. But it would be wrong to claim that one is a later version of the other one; they are packages in their own right, and can be upgraded independently from one another.
Hm, maybe I’m misunderstanding something, but then a user has to select the right package and when you link to an extension you have to possibly provide 3 links for each version of the “bar extender (check_mk X.Y)” package - or do I have a chance to link between packages within exchange.checkmk.com?