title: Interface 'Symfony\Component\HttpKernel\HttpKernelInterface' not found
body: <p>After upgrading from Symfony 2.3 to 2.8 I get the following error:</p>
  
  <blockquote>
    <p>Fatal error: Interface
    'Symfony\Component\HttpKernel\HttpKernelInterface' not found in
    app/bootstrap.php.cache on line 2629</p>
  </blockquote>
  
  <p>Already tried removing the vendor folder and doing a composer install.</p>
  
  <p>Any ideas?</p>