Recabinet 4.0.3 is a maintenance update and is recommended for all users. It addresses numerous bugs from 4.0.2, and continues to iterate on the engine for the forthcoming major 4.1 update. For a full list of changes, check the version history.
*UPDATE (April 5, 2015) – Please download and install the Mac version again if you used the original 4.0.3 installer that was posted yesterday. A critical fix was accidentally left out of the Mac version due to a sync error. This has been resolved.