[ci skip] Prepare 3.1.6 release
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index dcfe7b4..e5387cc 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -5,7 +5,7 @@
 Version 3.1.6
 =============
 
-Release Date: Not Released
+Release Date: Sep 25, 2017
 
 -  **Security**