title: DatePicker not available in XAML in Windows Phone 8.1 project retargeted from 8.0
body: <p>I've recently updated a Windows Phone 8 app to Windows Phone 8.1. I'm trying to add a <code>&lt;DatePicker /&gt;</code> control (newly available in Windows Phone 8.1) to the XAML but it's not available in my XAML. </p>
  
  <p>I get the errors:</p>
  
  <blockquote>
    <p>The name "DatePicker" does not exist in the namespace
    "<a href="http://schemas.microsoft.com/client/2007" rel="nofollow noreferrer">http://schemas.microsoft.com/client/2007</a>"</p>
  </blockquote>
  
  <p>and</p>
  
  <blockquote>
    <p>The type 'DatePicker' was not found. Verify that you are not missing
    an assembly reference and that all referenced assemblies have been
    built.</p>
  </blockquote>
  
  <p>and</p>
  
  <blockquote>
    <p>The tag 'DatePicker' does not exist in XML namespace
    '<a href="http://schemas.microsoft.com/winfx/2006/xaml/presentation" rel="nofollow noreferrer">http://schemas.microsoft.com/winfx/2006/xaml/presentation</a>'</p>
  </blockquote>
  
  <p>However, if I create a new Windows Phone app the <code>DatePicker</code> is available there.</p>
  
  <p>Also, I can create and add the DatePicker via the codebehind, just not in XAML.</p>
  
  <p>I have checked and can confirm the project is targeting Windows Phone 8.1, and as far as I can see I am referencing the correct assembly:</p>
  
  <p><img src="https://i.stack.imgur.com/1KwGv.png" alt="enter image description here"></p>
  
  <p>What do I need to do to make the DatePicker available in XAML?</p>