Jabber has been working without any problems in 3.0.0 but upon upgrading to 3.0.1 it has ceased to work and is giving errors both when updating the Jabber details in the ACP and when sending a Jabber message.

After some investigation it appears that the problem is in functions_jabber.php with this piece of code on lines 402-407

if ($second_time){     // If we are here for the second time after TLS, we need to continue logging in      $this->login();      return;}   

By taking this code out Jabber works again.