[master] 7e68fee Summarize changes for devs in 5.2.

[Geoff Simmons]

commit 7e68fee0ee0c10e9ce3a13627c1c9ea39be98994
Author: Geoff Simmons <geoff at uplex.de>
Date:   Wed Sep 13 13:35:11 2017 +0200

    Summarize changes for devs in 5.2.

diff --git a/doc/sphinx/whats-new/changes-5.2.rst b/doc/sphinx/whats-new/changes-5.2.rst
index de73237..7dced4d 100644
--- a/doc/sphinx/whats-new/changes-5.2.rst
+++ b/doc/sphinx/whats-new/changes-5.2.rst
@@ -73,6 +73,7 @@ News for authors of VMODs and Varnish API client applications
 
 *XXX: such news may include:*
 
+.. _whatsnew_abi:
 
 $ABI [strict|vrt]
 -----------------
@@ -93,6 +94,8 @@ by adding ``$ABI vrt`` to their VCC descriptor. The default value
 is ``$ABI strict`` when omitted, and all VMODs from the standard
 Varnish distribution have a strict requirement.
 
+.. _whatsnew_vsm_vsc_5.2:
+
 VSM/VSC API changes
 -------------------
 
@@ -138,6 +141,8 @@ should be called to release the segment again.
 
 All in all, this should be simpler and more robust now.
 
+.. _whatsnew_vrt_5.2:
+
 VRT API changes
 ---------------
 
@@ -149,6 +154,8 @@ New ``http_CollectHdrSep`` function, ``http_*`` symbols and associated
 data structures are part of the curated Varnish RunTime. Using them
 does not require strict ABI compliance.
 
+.. _whatsnew_vut_5.2:
+
 New VUT API
 -----------
 
diff --git a/doc/sphinx/whats-new/upgrading-5.2.rst b/doc/sphinx/whats-new/upgrading-5.2.rst
index 8a789d1..53291e4 100644
--- a/doc/sphinx/whats-new/upgrading-5.2.rst
+++ b/doc/sphinx/whats-new/upgrading-5.2.rst
@@ -120,9 +120,23 @@ This should again be useful for troubleshooting.
 
   * *XXX: ...*
 
-* *XXX: changes for developers?*
+* Changes for developers:
 
-  * *XXX: such as sanitizer flags?*
+  * The VSM and VSC APIs for shared memory and statistics have
+    changed, and may necessitate changes in client applications, see
+    :ref:`whatsnew_vsm_vsc_5.2`.
+
+  * Added the ``$ABI`` directive for VMOD vcc declarations, see
+    :ref:`whatsnew_abi`.
+
+  * There have been some minor changes in the VRT API, which may be
+    used for VMODs and client apps, see :ref:`whatsnew_vrt_5.2`.
+
+  * The VUT API (for Varnish UTilities), which facilitates the
+    development of client apps, is now publicly available, see
+    :ref:`whatsnew_vut_5.2`.
+
+  * *XXX: anything else, such as sanitizer flags?*
 
   * *XXX: ...*