I would allow schema extensions in minor updates (4.1/4.2/...). Micro updates would be maybe too confusing?
So I would prefer jpdl4.1.xsd I guess.
that is what my gutt feeling says as well. but i recall that in jbpm 3 we also did some (compatible) updates in micro releases.
should we think about strickt rules. or just follow instinct to what kind of updates we can do ?
Being to restrictive can result in switching off the schema validation in order to improve stuff or use new features (seen that a lot in projects)... So personally I wouldn't have too big problems if there are backward compatible changes in the Schema in Micro-Versions.
And follow your instinct is never the worst idea :-)
I agree, jpdl4.1.xsd is the best choce. As you say, there shouldn't be any xsd changed between micro releases