Update old documentation dropdown
diff --git a/documentation.html b/documentation.html
index 19b82d3..d655faf 100644
--- a/documentation.html
+++ b/documentation.html
@@ -47,6 +47,7 @@
<p class="body">The primary documentation reference material providing detailed information on the functions and algorithms within MADlib as well as background theory and references into the literature.</p>
<div class="select-documentation pointer point-down"><select id="latest-documentation" name="latest-documentation" size="1"><option value="">Older Documentation</option>
+<option value="docs/v2.1.0/index.html">MADlib v2.1.0</option>
<option value="docs/v1.21.0/index.html">MADlib v1.21.0</option>
<option value="docs/v1.20.0/index.html">MADlib v1.20.0</option>
<option value="docs/v1.19.0/index.html">MADlib v1.19.0</option>
