title: Microsoft Graph: Unable to Select ExtensionAttributes when using Delta Query?
body: <p>I've been using the Microsoft Graph to perform <a href="https://developer.microsoft.com/en-us/graph/docs/concepts/delta_query_users" rel="nofollow noreferrer">Delta Queries on Users</a>. My requirement is to return the values of <code>ExtensionAttributes</code> (custom properties synced to Azure AD from AD on-prem).</p>
  
  <p>The following request works: </p>
  
  <p><code>/v1.0/users?$select=extension_8928938292839829832_value</code></p>
  
  <p>And returns the extension attributes as desired: </p>
  
  <pre><code> "value": [
          {
              "extension_8928938292839829832_value": "String1",
          }
  </code></pre>
  
  <p>However when trying to use the Delta Query and including extension attributes: </p>
  
  <p><code>/v1.0/users/delta?$select=extension_8928938292839829832_value</code></p>
  
  <p>The value returned is just the basic user properties, NOT the requested extension value: </p>
  
  <pre><code> "value": [
          {
              "deletedDateTime": null,
              "accountEnabled": true,
              "assignedLicenses": [],
              etc, etc, etc
          },
  </code></pre>
  
  <p>I'm not sure if the extension values are exposed in the v1.0 Delta Query. </p>
  
  <p>Anyone have thoughts on how to approach this issue? Grabbing these extension attributes and using the delta query to track changes is vital to my solution.</p>