Will code that uses EWS developed against Exchange 2013 run on Exchange 2010? RRS feed

  • Question

  • Our code (Visual Studio .Net) makes extensive use of EWS to use data stored on customers' existing Exchange Server implementations. We signed up our first customer at the end of September 2019. Since then we cannot get beyond the login screen of our application, always getting 'user not found' whatever we try. The suspicion had been around SSL, or anti-virus settings or software, (NB the IIS Server log 'actively rejects' our application's attempts to connect). However, a specialist has completed a number of tests and has now proven there is nothing wrong with the customer's set up. The suspicion now is that the code, developed and tested against Exchange Server 2013 is not 'backwards compatible' with the customer's on-premise Exchange Server 2010 implementation. I can find MS Doc info about EWS on Exchange 2010 being forward compatible but not the other way around. Can anybody conform, either way, if this should work (or not)?
    Wednesday, December 4, 2019 8:30 AM

All replies

  • Hi WilliamIrvine5, 

    Welcome to the Exchange Server forum. This forum is for questions and feedback related to Exchange server. Since your question is more related to Exchange development, I'll move it to a more appropriate forum: Exchange Server Development


    Kyle Xu

    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact

    Thursday, December 5, 2019 6:23 AM
  • Thanks Kyle - what's the URL to my entry on Exchange Server Development?
    Thursday, December 5, 2019 3:16 PM