Exchange 2013 – Coexistence with previous products (Updated)

Exchange 2013 is now available in Preview form for an anticipated launch late this year or early next.

If you are thinking of waiting for the new products before you migrate from Exchange 2003, please be aware of the following information:-

Exchange Server Coexistence

As is standard practice, Microsoft will not support more than two previous versions of a product. This means that there will not be any coexistence capability between Exchange 2013 and Exchange 2003. Therefore to migrate from 2003 to 2013 will require the additional step of migrating onto Exchange 2010 first, and removing all trace of Exchange 2003, before you can migrate onto Exchange 2013.

Active Directory Requirements

Active Directory is required to contain at least one Windows 2008, 2008R2 or 2012 Domain Controller.

Client Restrictions

Outlook clients earlier than Outlook 2007 are not supported. Email clients on Mac operating systems that require DAV, such as Entourage 2008 for Mac RTM and Entourage 2004, are not supported.

Exchange 2013 Preview supports the following minimum versions of Microsoft Office Outlook and Microsoft Entourage for Mac:

  • Outlook      2013 Preview
  • Outlook      2010 SP1 with April 2012 Cumulative Update
  • Outlook      2007 SP3 with July 2012 Cumulative Update
  • Entourage      2008 for Mac, Web Services Edition
  • Outlook      for Mac 2011

Also note that Outlook 2013 Preview will not connect to Exchange 2003.


Since Exchange 2013 has now been through RTM and has now become GA ( you might think you can move into co-existence, this unfortunately is not the case. Microsoft have stated that the required Service Packs (SP3 for 2010, SP3 RU9 for 2007) won’t be made available until Q1 2013. This means that, unless you want to install a “green field” system, you will have to wait until next year before you can look at introducing Exchange 2013 into your environment.

This is very frustrating but as soon as I can get hold of the SP I’ll be testing the co-existence capabilities of 2013.