About the update

Mail Update for Mavericks includes improvements to general stability and compatibility with Gmail, including the following:

• Fixes an issue that prevents deleting, moving, and archiving messages for users with custom Gmail settings
• Addresses an issue that may cause unread counts to be inaccurate
• Includes additional fixes that improve the compatibility and stability of Mail

Installing the update

• You should back up your system before installation. To do this you can use Time Machine.
• You may experience unexpected results if you have third-party system software modifications installed, or if you've modified the operating system through other means.
• Choose Apple menu () > Software Update to check for the latest Apple software via the Mac App Store, including this update.
  Other software updates available for your computer may appear, which you should install. Note that an update's size may vary from computer to computer when installed using Software Update. Also, some updates must be installed prior to others. Use Software Update until it reports "No Updates Available".
• Do not interrupt the installation process once you have started to update your system.

You can also download the manual update installer. This is a useful option when you need to update multiple computer, but only want to download the update once. Standalone installers are available from Apple Support Downloads.