Exchange 2010 Service Pack 3 Update Rollup 6 Released

Deploying Exchange Server 2010 SP3 Update Rollup 6

The standard order of deployment for Exchange Server updates applies.

1. Client Access servers, starting with the internet-facing ones. See this article for how to patch a CAS array. http://thiyagarajanradhakrishnan.blogspot.in/2014/08/how-to-install-updates-on-exchange_30.html
2. Hub Transport servers
3. Unified Messaging servers
4. Mailbox servers. See this article for how to patch a Database Availability Group. http://thiyagarajanradhakrishnan.blogspot.in/2014/08/how-to-install-updates-on-exchange_88.html  
5. Edge Transport servers