Tonight I was able to fix bug 813 (see 837 for details). This is the last blocker bug for the 0.4 release. I merged a few patches there were sitting around. I've also fixed and issue with changes to metadata not being relayed to the GUI as the file having been changed. With these bugs fixed 0.4 is in a state that I feel is ready for release.
I have little experience with building releasable, binary packages for OS X and Windows. So It will be a few days (maybe weeks) before they're out. There is a strong possibility I need to buy a copy of Windows and that will take a few days to get. Also, I need to actually setup a Windows build environment. I'm going to try building using an old netbook I have (it's the only computer I can use that has a copy Windows for building packages.
I don't want to do this release piece by piece so I'm going to wait to release all packages (OS X and source) together. Also, I plan to put out an RC 2 before 0.4 final. The RC 2 will be exactly the same as 0.4 final as far as the code is concerned. RC 2 is to make sure I package Sigil properly. It won't do any good to put out 0.4 that can only be run if you have all of the development libraries Sigil uses installed independently of Sigil.