The OS X Mavericks v10.9.1 Update is recommended for all OS X Mavericks users. It improves the stability, compatibility, and security of your Mac.

This update includes:

-Improved support for Gmail in OS X Mail, and fixes for users with custom Gmail settings Improves the reliability of Smart Mailboxes and search in Mail
-Fixes an issue that prevented contact groups from working properly in Mail
-Resolves an issue that prevented VoiceOver from speaking sentences that contain emoji
-Fixes an issue that prevented iLife and iWork apps from updating on non-English systems
-Addresses an issue that may cause multiple prompts to unlock “Local items” keychain
-Addresses an issue that may cause Japanese keyboards to retain a previously used language
-Resolves issue that prevents a Contact group name from populating the address field
-Includes Safari 7.0.1
-Fixes an issue that could cause Safari to become unresponsive when filling out forms on fedex.com, stubhub.com, and other websites Improves Credit Card Autofill compatibility with websites
-Improves VoiceOver compatibility with facebook.com
-Updates Shared Links periodically when open in the Safari Sidebar

Some useful updates in this release.