added link to upgrade instructions
diff --git a/user_guide/installation/upgrading.html b/user_guide/installation/upgrading.html
index b6ac633..32907cd 100644
--- a/user_guide/installation/upgrading.html
+++ b/user_guide/installation/upgrading.html
@@ -65,6 +65,7 @@
<p>Please read the upgrade notes corresponding to the version you are upgrading from.</p>
<ul>
+<li><a href="upgrade_152.html">Upgrading from 1.5.0 or 1.5.1 to 1.5.2</a></li>
<li><a href="upgrade_150.html">Upgrading from 1.4.1 to 1.5.0</a></li>
<li><a href="upgrade_141.html">Upgrading from 1.4.0 to 1.4.1</a></li>
<li><a href="upgrade_140.html">Upgrading from 1.3.3 to 1.4.0</a></li>