--- a/CHANGES.html	Wed Aug 15 12:27:15 2018 -0700
+++ b/CHANGES.html	Wed Aug 15 13:19:57 2018 -0700
@@ -105,6 +105,7 @@
   <li> When using on newer compilers, new warnings may trigger build failures.
 The --disable-werror flag can be passed to Waf at configuration time to turn
 off the Werror behavior.</li>
+  <li> GTK+3 libraries (including PyGObject, GooCanvas2) are needed for the Pyviz visualizer, replacing GTK+2 libraries.</li>
 </ul>
 <h2>Changed behavior:</h2>
 <ul>