[#1083] Add notes about Apache and extensions to the patch release as…

… well

doc/upgrade-package-to-patch-release.rst

@@ -33,12 +33,40 @@ minor release they belong to, so for example CKAN ``2.0``, ``2.0.1``,
 
     sudo dpkg -i python-ckan_2.0_amd64.deb
 
-   This will **not** replace or modify any configuration files that you already
-   have on the server, including the CKAN config file or any |apache| or
-   |nginx| configuration files.
-
    Your CKAN instance should be upgraded straight away.
 
+   .. note::
+
+      If you have changed the |apache| or |nginx| configuration files, you will
+      get a prompt like the following, asking whether to keep your local changes
+      or replace the files. You generally would like to keep your local changes
+      (option ``N``, which is the default), but you can look at the differences
+      between versions selecting option ``D``::
+
+       Configuration file `/etc/apache2/sites-available/ckan_default'
+        ==> File on system created by you or by a script.
+        ==> File also in package provided by package maintainer.
+          What would you like to do about it ?  Your options are:
+           Y or I  : install the package maintainer's version
+           N or O  : keep your currently-installed version
+             D     : show the differences between the versions
+             Z     : start a shell to examine the situation
+        The default action is to keep your current version.
+       *** ckan_default (Y/I/N/O/D/Z) [default=N] ?
+
+      Your local CKAN configuration file in |config_dir| will not be replaced.
+
+   .. note::
+
+     The install process will uninstall any existing CKAN extensions or other
+     libraries located in the ``src`` directory of the CKAN virtualenv. To
+     enable them again, the installation process will iterate all folders in
+     the ``src`` directory, reinstall the requirements listed in
+     ``pip-requirements.txt`` and ``requirements.txt`` files and run
+     ``python setup.py develop`` for each. If you are using a custom extension
+     which does not use this requirements file names or is located elsewhere,
+     you will need to manually reenable it.
+
    .. note::
 
       When upgrading from 2.0 to 2.0.1 you may see some vdm related warnings