Following a conversation and some debugging with Stéphane and James, the conclusion is that this is a bug in upstart which is failing to re- exec/reload itself and so doesn't see php-fpm upstart job.
** Package changed: php5 (Ubuntu) => upstart (Ubuntu) ** Changed in: upstart (Ubuntu) Importance: Medium => High ** Changed in: upstart (Ubuntu) Status: Confirmed => Triaged ** Summary changed: - php-fpm service does not automatically restart after upgrade + New upstart jobs are not detected in a P to T upgrade -- You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to php5 in Ubuntu. https://bugs.launchpad.net/bugs/1272788 Title: New upstart jobs are not detected in a P to T upgrade To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/upstart/+bug/1272788/+subscriptions -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs