If you're using <
SpamSieve>, you'll probably get a notice about the update now available. I haven't made the 10.9.3 OS update and probably won't until next week. But I noticed something I did not know about SpamSieve today. The alert/update notice mentioned that it is best to update SpamSieve
before updating the OS. Here's part of what its Help page says about the reasoning:
QUOTE(SpamSieve->Help->Apple Mail–Specific Questions->Why does SpamSieve always need an update when Mac OS X is updated?)
Update SpamSieve Before Updating Mac OS X
The smoothest way to update Mac OS X and SpamSieve is to update SpamSieve before updating Mac OS X.
The reason for this is that if you update Mac OS X first, and then open Mail, Mail will not load the old version of the SpamSieve plug-in. Without the plug-in loaded, you will not see the SpamSieve commands in Mail’s Message menu, and Mail will move good messages to the spam mailbox without consulting SpamSieve. If you get into this situation, quit Mail and then update SpamSieve. The next time you launch SpamSieve, it should detect that the plug-in was disabled by an OS update and reinstall the plug-in. If this does not happen automatically, you can choose Install Apple Mail Plug-In from the SpamSieve menu.
I think this is the only app/developer I know that does this. OTOH, others may simply say something to the effect that their update is for "compatibility" with an OS update; same effect.