title: Adding field to WCF data contract breaks clients?
body: <p>I have a WCF service that returns a class that implements IExtensibleDataObject. I need to add a new field to this class.  I updated the DataContract interface and made the change to the class.  Now when I try to run my client application I get the following error:</p>
  
  <blockquote>
    <p>Could not load file or assembly
    'xxx.yyyy.zzzz, Version=1.3.9.26111,
    Culture=neutral,
    PublicKeyToken=b09e2f3e9b5894f0' or
    one of its dependencies. The located
    assembly's manifest definition does
    not match the assembly reference.
    (Exception from HRESULT: 0x80131040)</p>
  </blockquote>
  
  <p>The AssemblyVersion of the WFC class has been changed - does that break client?</p>
  
  <p><strong>EDIT:</strong></p>
  
  <p>There are clients in production that use this service.  I do not want to make them update their service reference and redeploy their clients for this simple change if possible.</p>