CiviMail - Error 500 when tracking clickthroughs

Question

We have recently upgraded to CiviCRM 4.7.0, and we have Drupal 7.41

As part of the upgrade process, I upgraded PHP to 5.6.17

Most things work brilliantly, but when we have link tracking enabled on a CiviMail email we get this error:

Fatal error: Call to undefined function drupal_add_http_header() in /home/ace/public_html/sites/all/modules/civicrm/CRM/Utils/System/Drupal.php on line 789

An example URL is https://acenterprises.org.uk/sites/all/modules/civicrm/extern/url.php?u=1535&qid=864040

There's nothing recorded in the HTTP Error Log - can anyone give me any clues on debugging this error?

Thanks!

Answer 1

This seems to be an issue with 4.7 and 4.7.1: https://issues.civicrm.org/jira/browse/CRM-17953

The issue has a workaround solution, and the full fix will be linked from that issue when it has been implemented.