diff --git a/doc/userguide/devguide/README.md b/doc/userguide/devguide/README.md
index e5086ced2c..c5d80eb91e 100644
--- a/doc/userguide/devguide/README.md
+++ b/doc/userguide/devguide/README.md
@@ -1,14 +1,9 @@
 # Suricata Developer Guide
 
-This directory contains the Suricata Developer Guide. The
-[Sphinx Document Generator](http://sphinx-doc.org) is used to build the
-documentation. For a primer os reStructuredText see the
-[reStructuredText Primer](http://sphinx-doc.org/rest.html).
+This directory contains the Suricata Developer's Guide. It is built as part of the Suricata Userguide.
 
-## Verifying Changes
+The Sequence Diagrams seen in the Transactions documentation are generated with Mscgen. Mscgen is a small program to parse Message Sequence Charts that can be represented as text and can then converted to image.
 
-There are a number of output formats to choose from when making the source documentation locally (e.g. html, pdf, man).
+If you need to update the diagrams, please edit the ``.msc`` files present in the diagrams directory (extending/app-layer/diagrams). Once those have been changed, in the ``scripts`` directory (in the main Suricata dir) there's a scrip that will generate images for all files: ``generate-images.sh`` (you'll have to install Mscgen for that to work).
 
-The documentation source can be built with `make -f Makefile.sphinx html`. Substitute the 'html' word for desired output format.
-
-There are different application dependencies based on the output desired.
+More info about Mscgen can be found at: https://www.mcternan.me.uk/mscgen/