The 10.7.3 update is recommended for all OS X Lion users and includes general operating system fixes that improve the stability, compatibility, and security of your Mac including fixes that:
  • Add Catalan, Croatian, Greek, Hebrew, Romanian, Slovak, Thai, and Ukrainian language support
  • Address issues when using smart cards to log into OS X
  • Resolve issues authenticating with directory services
  • Address compatibility issues with Windows file sharing

Visit the Apple website for more information