This release is a maintenance release of the 0.8.x series and fixes a few critical bugs that could cause Sigil to crash. You can find binary packages here and the change log, here.
Finally, the sha256 checksum for the checksum file is 732773ec4fc73ab2ba29584130833b53d96c6c1296c433d889f2cd4b55d565be. The Mac package is signed by my signing key (John Schember) and 10.9.5 is the minimum OS X version but it was built and tested on 10.10. The Windows builds were built on Windows 7.
Edit April 14, 2015.
There was an issue with the Mac Package where it would crash instead of opening. A new build has been uploaded. The new checksum for the checksum file is b05880c62ecd63a20225e13fc3868ea5520fe5f2e498842c542b1f32d525fee1.