Hey whats this DWGgateway

Backward compatibility is relatively easy when all you are talking about is data entities / geometry (a point's a point, line's a line, etc.). When the functions that create the data entities are considered the problem is apparent (that's assuming there are in fact new functions in the newer release). That's the gist of it, anyway, and it does present real problems. Fact-o-the-matter is it can be done; witness the $20k + cross platform feature enabled translators. When they can't duplicate a feature they create a non-parametric surface (simplified, generalized, hearsay explanation). If there's a market, there's a way....