Updating Microsoft Windows Small Business Server 2011 (SBS2011)

There are several important updates that need to be manually installed on Microsoft Windows Small Business Server 2011. Download the files below. Before installing them, perform a full server backup. Then install the updates in this order:

1. Microsoft Windows Server 2008 R2 Service Pack 1
   (download the X64 file only as SBS2011 never came in X86/32-bit version).
2. Microsoft Windows Small Business Server 2011, Update Rollup 4
   (optional but highly recommended)
3. Microsoft Exchange Server 2010 Service Pack 3
4. Microsoft Exchange Server 2010 Service Pack 3, Update Rollup 6
   (optional but highly recommended)
5. Microsoft Sharepoint Foundation 2010 Service Pack 2

Recommended: reboot between each step and take a backup between each step.

You'll need a couple of hours for the average server to install all of the updates. 

How to determine the version of Exchange and Exchange Service Pack level

http://support.microsoft.com/kb/152439

Also try running the following commandlet from an Exchange Management Shell:

Get-ExchangeServer -Identity ExServer1 | Format-Table Name, AdminDisplayVersion

Full list of the Exchange Server Updates with build numbers and release dates:

https://technet.microsoft.com/en-us/library/hh135098(v=exchg.150).aspx 

Create Self-Signed Certificates for Exchange 2010

http://careexchange.in/how-to-use-a-self-signed-certificate-in-exchange-2010/

Also make sure to download the CA root certificate from step 16 and install the CA Root Cert onto all client computers.