diff --git a/mozilla/webtools/bugzilla/.bzrrev b/mozilla/webtools/bugzilla/.bzrrev
index 8dd4494ba88..59ada7f7150 100644
--- a/mozilla/webtools/bugzilla/.bzrrev
+++ b/mozilla/webtools/bugzilla/.bzrrev
@@ -1 +1 @@
-9263
\ No newline at end of file
+9264
\ No newline at end of file
diff --git a/mozilla/webtools/bugzilla/.gitrev b/mozilla/webtools/bugzilla/.gitrev
index b50f0eaad1a..78037da4793 100644
--- a/mozilla/webtools/bugzilla/.gitrev
+++ b/mozilla/webtools/bugzilla/.gitrev
@@ -1 +1 @@
-92e11c7c13e167cfe7ba13ec415fd636c290b4ae
\ No newline at end of file
+645d58e1763156d24c512c9ecaa0222ef5f4c795
\ No newline at end of file
diff --git a/mozilla/webtools/bugzilla/docs/en/rst/upgrading/index.rst b/mozilla/webtools/bugzilla/docs/en/rst/upgrading/index.rst
index 937fdaeea3a..138c1d260de 100644
--- a/mozilla/webtools/bugzilla/docs/en/rst/upgrading/index.rst
+++ b/mozilla/webtools/bugzilla/docs/en/rst/upgrading/index.rst
@@ -13,3 +13,4 @@ Upgrading Bugzilla
    migrating-from-cvs
    migrating-from-a-tarball
    upgrading-with-a-tarball
+   upgrading-customizations
diff --git a/mozilla/webtools/bugzilla/docs/en/rst/upgrading/overview.rst b/mozilla/webtools/bugzilla/docs/en/rst/upgrading/overview.rst
index e779caf5222..c23cd071037 100644
--- a/mozilla/webtools/bugzilla/docs/en/rst/upgrading/overview.rst
+++ b/mozilla/webtools/bugzilla/docs/en/rst/upgrading/overview.rst
@@ -23,9 +23,9 @@ Before Git, we used to use Bazaar and, before that, CVS. If your installation
 of Bugzilla consists of a checkout from one of those two systems, you need to
 upgrade in three steps:
 
-1. upgrade to the latest point release of your current Bugzilla version;
-2. move to Git while staying on exactly the same release;
-3. upgrade to the latest Bugzilla using the instructions for :ref:`upgrading-with-git`.
+1. Upgrade to the latest point release of your current Bugzilla version.
+2. Move to Git while staying on exactly the same release.
+3. Upgrade to the latest Bugzilla using the instructions for :ref:`upgrading-with-git`.
 
 See :ref:`migrating-from-bazaar` or :ref:`migrating-from-cvs` as appropriate.
 
@@ -38,12 +38,15 @@ If you aren't sure which of these categories you fall into, to find out which
 version control system your copy of Bugzilla recognizes, look for the
 following subdirectories in your root Bugzilla directory:
 
-* :file:`.git`: you installed using Git - follow :ref:`upgrading-with-git`
-* :file:`.bzr`: you installed using Bazaar - follow :ref:`migrating-from-bazaar`
-* :file:`CVS`: you installed using CVS - follow :ref:`migrating-from-cvs`
-* none of the above: you installed using an old tarball - follow
-  :ref:`migrating-from-a-tarball`
+* :file:`.git`: you installed using Git - follow :ref:`upgrading-with-git`.
+* :file:`.bzr`: you installed using Bazaar - follow :ref:`migrating-from-bazaar`.
+* :file:`CVS`: you installed using CVS - follow :ref:`migrating-from-cvs`.
+* None of the above: you installed using an old tarball - follow
+  :ref:`migrating-from-a-tarball`.
 
 It is also possible, particularly if your server machine does not have and
 cannot be configured to have access to the public internet, to upgrade using
 a tarball. See :ref:`upgrading-with-a-tarball`.
+
+Whichever path you use, you may need help with
+:ref:`upgrading-customizations`.
diff --git a/mozilla/webtools/bugzilla/docs/en/rst/upgrading/upgrading-customizations.rst b/mozilla/webtools/bugzilla/docs/en/rst/upgrading/upgrading-customizations.rst
new file mode 100644
index 00000000000..c99c6a9f7d5
--- /dev/null
+++ b/mozilla/webtools/bugzilla/docs/en/rst/upgrading/upgrading-customizations.rst
@@ -0,0 +1,20 @@
+.. _upgrading-customizations:
+
+Upgrading a Customized or Extended Bugzilla
+###########################################
+
+If your Bugzilla has been customized or uses extensions, you will need to
+make your customizations or extensions work with your new version of Bugzilla.
+If this is the case, you are particularly strongly recommended to do a test
+upgrade on a test system and use that to help you port forward your
+customizations.
+
+If your extension came from a third party, look to see if an updated version
+is available for the version of Bugzilla you are upgrading to. If not, and
+you want to continue using it, you'll need to port it forward yourself.
+
+If you are upgrading from a version of Bugzilla earlier than 3.6 and have
+extensions for which a newer version is not available from an upstream source,
+then you need to convert them. This is because the extension format changed
+in version 3.6. There is a file called :file:`extension-convert.pl` in the
+:file:`contrib` directory which may be able to help you with that.