Apple has released 10.9.5 update for OS X Mavericks. This update is recommended for all Mac users and it includes bug fixes and security updates for Mac

The update fixes the reliability issue of VPN connections that use USB smart cards for authentication and reliability of accessing files located on SMB servers. It also includes a updated version of Safari 7.0.6.

For enterprise users, it has fixes for group membership in large networks and it allows authentication when roaming on 802.1x networks which use EAP-TLS.

You can update it through Mac App Store or downloading a standalone installer fro Apple Support page.