Is there a changelog somewhere? 
Nope, but here is a basic rundown of CVS commits since RC2:
 - "Y" targetting bug fixed
 - fix for warpout if player is docked to something
 - FBO fixes to allow better use in scripts
 - fix error handling in ds_get_free_channel() for OpenAL
 - fix super-functional counter-measures (fixes repeating evade sound and incompatible network packet and restores game balance)
 - make sure to use mission specified envmap (if one exists) over a static generated one
 - add -disable_fbo cmdline option to help troubleshoot ATI render errors with -env (allow -env to work with default cubemap or mission specified envmap only)
 - fix -img2dds related Assert()/crash on really small images that tried to rescale
 - fix green outline on PCX images compressed with -img2dds or when using -pcx32
 - disable depth render buffer that some ATI cards seem to have trouble with
 - disable automatic mipmaps for generated envmaps since the chain gets broken (it produces some black images for unknown reasons)
 - plus various debug related and big endian fixes
Windows Voice Recognition : Failed to load resource, failed to init. 
Yep, I think it's just broken in the code.  Assume it won't ever be back unless RandomTiger returns to fix it.