The Microsoft Exchange Server team has announced the upcoming availability of Service Pack 1 for Exchange Server 2013, scheduled for release in “early 2014”.

Among the changes and improvements planned for Service Pack 1:

  • Support for running Exchange Server 2013 on Windows Server 2012 R2
  • The return of the Edge Transport server role
  • S/MIME support for Outlook Web App
  • Many more fixes and improvements

The team also said that Service Pack 1 is essentially CU4. Considering we are at CU2 right now that leaves open the question of when CU3 will be released.

UC Architect Dave Stork noticed in the last few days a number of KB articles were published that listed fixes that were included in CU3, however those KB articles have since been removed. The publishing of specific KBs like that usually coincides with the release of an update or service pack. In their blog post about SP1 Microsoft did hint that more info about CU3 is “imminent”, so perhaps the KB articles were accidentally published too soon, and were removed until CU3 is formally released. I’m sure we’ll find out soon.


About the Author

Paul Cunningham

Paul is a former Microsoft MVP for Office Apps and Services. He works as a consultant, writer, and trainer specializing in Office 365 and Exchange Server. Paul no longer writes for


  1. Peter Nørredal

    Hi Paul
    Yes I read the 100 DB pr. server in Enterprise CU2 version, but I also read somewhere that MS scaled it do to 50.

    If not true thats just super great for us – and we can have 50 active and 50 passive DB pr. server and still hold all the Passive ones on either of the servers.


    Thanks 🙂

      1. Peter Nørredal

        Thanks Paul
        We have a 2 server – Exchange 2013 DAG setup, with passive Database copies, for every active one.
        So that leaves me with a limit of 25 Active on each server, in order to Mount every passive database from the other server, in case of emergency.

        So, I guess the solution i more servers (joining the existing DAG) in order to have more active Dtabases running at the same time. Or creating a new DAG, with new servers – and then setup the 25/25 of active/Passive databses on these server as well ?

        Do you know what SP1 will bring us, in regards to the number of databases pr. server ?


        1. Avatar photo
          Paul Cunningham

          Why 25/25? In that document I linked to it says:

          “Enterprise Edition can scale to…. 100 mounted databases per server in Cumulative Update 2 (CU2) and later versions”

          CU3 is the current version and nobody should be deploying anything earlier than that anyway.

          There has been no announcement of changes in SP1 to the number of databases per server. I would expect it to stay the same.

  2. Peter Nørredal

    Hi All
    Can any one tell me the maximum number of databases i Exchange 2013 Enterprise Cu3 ?
    I´m a bit confused searching the net.

    It seems that with Exchange 2013 CU2 the maximum number of databases was 100, but later on this was changed to a maximum of 50 (don´t know exactly why)

    Now with the upcoming release of Exchange 2013 CU4 (also know as SP1) I Wonder what the maximum number of databases would be.


  3. Dave Kalwiwshky

    We are on CU3 and it introduced a bug that breaks Windows XP clients from being able to open Public Folders. I wish I would not have installed CU3.

    SP1 is supposed to fix the problem.

  4. Andy B

    I was told by a Microsoft TAM on Wendesday, that CU3 had been pulled for unknown reasons. They are still telling me it is due to be released in a week or two.

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