So that was my conviction, too. However, in my tests it seems like upgrading to a version a model hasn't seen is for some reason problematic, in spite of giving it the complete docs, examples of new API usage etc. This happens even with small snippets, even though they can deal with large code fragments with older APIs they are very "familiar" with.

Okay so less of a "this isn't going to work at all" and more just not ready for prime-time yet.