diff --git a/ChangeLog.rst b/ChangeLog.rst
index 4a16be95..1633bac7 100644
--- a/ChangeLog.rst
+++ b/ChangeLog.rst
@@ -1,3 +1,6 @@
+4.0.1 - TBD
+-----------
+
 4.0.0 - 2017-06-27
 ------------------
 
diff --git a/fmt/format.h b/fmt/format.h
index 88ab31a3..1b727965 100644
--- a/fmt/format.h
+++ b/fmt/format.h
@@ -43,7 +43,7 @@
 #undef FMT_INCLUDE
 
 // The fmt library version in the form major * 10000 + minor * 100 + patch.
-#define FMT_VERSION 40000
+#define FMT_VERSION 40001
 
 #ifdef _SECURE_SCL
 # define FMT_SECURE_SCL _SECURE_SCL