Comment 1 for bug 1678131

These changes went into 2.4.17-1 which is >=Xenial.
So as requested only Trusty is needed.

The changes once isolated look rather small => http://paste.ubuntu.com/24306087/

2.4.7-1ubuntu4.14 was burnt by https://bugs.launchpad.net/ubuntu/+source/apache2/+bug/1534538, so preparing a 2.4.7-1ubuntu4.15 might be the right thing to do.

The first two chunks somewhat apply, yet the third one does not.
There is no execute_deferred_actions (nor similar) in the old postinst.
If anything there is a line like
> for link in /etc/apache2/mods-enabled/*.load ; do
IMHO this section is not needed as it is about disabling outdated modules that are no more provided and not the MPM switch this is about.

So chunk 2/3 should do it IMHO.
I hope on Wednesday on the next USBSD [1] (this wedenesday) somebody with more apache experience might help otherwise I might try.

[1]: https://naccblog.wordpress.com/2017/03/24/usbsd-1-goals-inaugural-ubuntu-server-bug-squashing-day/