[ci skip] Mark the start of 3.1.9 development
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index 371b495..d0989da 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -2,6 +2,12 @@
 Change Log
 ##########
 
+Version 3.1.9
+=============
+
+Release Date: Not Released
+
+
 Version 3.1.8
 =============