title: How do I know that 3D Secure 2 authentication works after upgrading to stripe.js version 3
body: <p>I have updated a site so it uses latest stripe-php (6.39.0) and it now loads stripe.js version 3. I’ve made all the necessary changes to my code so that my credit card fields are now displayed using Stripe Elements. Test transactions work and I have updated the live site and real payments are being excepted.</p>
  <p>The reason I made this update was because I was informed by stripe that I needed to upgrade the site so that its stripe integration will work with Strong Customer Authentication (SCA) which is required in the EU by September 2019.</p>
  <p>Stripe has different credit card test numbers you can use to test things that arise when processing payments. This numbers can be found here: <a href="https://stripe.com/docs/testing#cards" rel="nofollow noreferrer">https://stripe.com/docs/testing#cards</a></p>
  <p>4000000000003220 simulates a transactions where 3D Secure 2 authentication must be completed. But when I use this code stripe turns down payment and returns the message:</p>
  <blockquote>
  <p>&quot;Your card was declined. This transaction requires authentication. Please check your card details and try again.&quot;</p>
  </blockquote>
  <p>Does this mean that 3D Secure 2 is working or not?</p>
  <p>In the real world it would open a window with an interface from the customer's card issuer. So I not sure wether my integration is working or not. As said before payments are being excepted butI need to ready when Strong Customer Authentication is required in September.</p>