There is a first update to the Mavericks operating system from Apple.
About the OS X Mavericks v10.9.1 Update displays some (perhaps all) of the feature changes/fixes in this update. None appear to have a direct effect on the operation of Fusion, however (but, it might).
About the security content of Safari 6.1.1 and Safari 7.0.1 displays security issues addressed in this update, which is likely a more important reason to get this update, as there's an effect on autofill.