The 10.6.3 update is recommended for all servers currently running Snow Leopard Server version 10.6 and includes general operating system fixes that enhance the stability, compatibility and security of your server, as well as specific fixes for:

configuring accounts in Server Preferences when bound to an external directory service
CalDAV handling of Unicode text and attachments
stability and reliability of Podcast Capture remote camera recordings
submitting content into Podcast Producer using mv and cp command-line tools
preventing time drift when capturing dual-source video in Podcast Capture
syncing Software Update catalogs behind unauthenticated proxy servers
upgrading and importing records from older Open Directory servers
password expiration notifications for Mobile Account users
using Server Admin to connect to servers in IPv6 environments
creating NetRestore images from volumes with fragmented catalog files
ordering of items in System Image Utility "Add Packages and Post-Install Scripts" action
using Internet Explorer with web-based calendar, wiki, email rules and password reset
adding and removing imported users in Server Preferences
synchronizing Portable Home Directory content
using iCal web interface within select time zones
previewing and capturing dual-source video in Podcast Capture
server-side filtering of incoming mail messages
using chained digital certificates for mail services
creating images with System Image Utility
automating installation of NetRestore images
preventing brute force password attacks
using sudo command with authenticated Open Directory binding
binding to Active Directory domains with invalid service records
creation of mobile accounts for Active Directory users
correcting a problem that would cause the Software Update cache to grow excessively
reliability of services using Grand Central Dispatch
duplicate serial number alerts on servers with multiple network interfaces

System Requirements
Mac OS X 10.6.2 Server