[NTG-context] Which version to use for MathML?

Hi all, I tried a few mathml examples with 2012.05.30 and the latest beta (test script attached). The 20120530 version fails with eqn1, which uses presentation mathml, but works with eqn using content mathml. The latest beta generates doesn't work with either equations. I see a lot of mathml related changes recently, with the file x-mathml.mkiv come and go away. Which version should I go with to get presentation mathml work? thanks and regards, shenchen