Much more could be said, but I hope this helps understand the
overall concepts a bit better.

I've also taken the freedom to reword "cluster" in the director
concept to "load balancer" because at least in my experience, the
former is used more for some form of tighter binding between nodes,
while the latter is a common term for what directors usually do.

Text mostly taken from ecdebdc7

We copy vmods using unique filenames for ages

Ref: 3cf58766

Original text from 2014: 920541a8

IMO the release notes are not an appropriate place to point to a
third-party VMOD.

Not ready to tackle the Python2/Python3 monster a week before release.

We have settled on using 'Upgrading' to list changes like this, while
'Changes' is a free-form prose overview ("about this release").

Helps: #2764

Fixes:	#2773

The fact that the previous object was IMS/INM eligable does not make
one created from it eligable as well.

Also test for the miss + hfm case with IMS/INM

Fixes #2763

it really is about time we rename OC_F_PASS -> OC_F_HFM, but
my recent cleanup attempt included too much change before the release