I'm really sorry about this, but I seem to have once again invoked the curse of incremental delays by giving out an optimistic release date. I've been working as fast as I can on the Meraxis & centaur transport content, but it's simply taken me longer to get the dialogue frameworks implemented and tested than I expected.
I've got the aforementioned content frameworks finished, but I'll need another couple of days to get the demonic centaur encounters into a working state, and as soon as that's done I'll release the preview with placeholder dialogue. I'll then get a preview hotfix out as soon as possible after that to fill in the placeholders.
I'm sorry for not only how long this is taking but also for disappointing you all again with another missed deadline. I won't give a fixed deadline for 0.4.0.5, but it really shouldn't be more than 2-3 days now...