joomla/joomla-cms — pull request #5247 by JoomliC (2014-11-29 14:18:15+00:00)
Title: B/C issue on $app->redirect($url, $msg)

I've found a B/C issue in 3.4.0-alpha related to a change done in /libraries/joomla/application/web.php, line 549 https://github.com/joomla/joomla-cms/pull/4292

If a third-party extension uses the deprecated $app->redirect($url, $msg), as $msg is not numeric, it will return a error 0 You have not supplied a valid HTTP 1.1 status code