diff --git a/doc/src/history.adoc b/doc/src/history.adoc
index e75e736375..f02b1f9fc4 100644
--- a/doc/src/history.adoc
+++ b/doc/src/history.adoc
@@ -1,6 +1,14 @@
 [[b2.history]]
 = History
 
+== Version 4.0.1
+
+This patch release fixes a minor issue when trying to configure toolsets that
+override the toolset version with a non-version tag. Currently this is only
+known to be a problem if you: (a) configure a toolset version to something
+like "`tot`" (b) in Boost 1.72.0 when it creates cmake install artifacts.
+Fix for this was provided Peter Dimov.
+
 == Version 4.0.0
 
 After even more years of development the landscape of build systems has changed
diff --git a/src/engine/patchlevel.h b/src/engine/patchlevel.h
index 80d29b23fe..c47916adea 100644
--- a/src/engine/patchlevel.h
+++ b/src/engine/patchlevel.h
@@ -13,4 +13,4 @@ Distributed under the Boost Software License, Version 1.0.
 
 #define VERSION_MAJOR 4
 #define VERSION_MINOR 0
-#define VERSION_PATCH 0
+#define VERSION_PATCH 1