docs: Update link to the right version of developer's guide
Change-Id: I6a39507df56141d648728bebc9f6305584ecb067
diff --git a/docs/index.rst b/docs/index.rst
index 74f568d..94157be 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -34,7 +34,7 @@
**Additional documentation**
-* `NFD Developer's Guide <http://named-data.net/wp-content/uploads/2014/07/NFD-developer-guide.pdf>`_
+* `NFD Developer's Guide <http://named-data.net/techreport/ndn-0021-3-nfd-developer-guide.pdf>`_
A comprehensive guide to the design and implementation of NFD. The developer's guide also contains
suggestions and hints for anyone wanting to modify or extend NFD.