diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8b88e2b68a9..74517cc465e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,7 +5,7 @@ project (PIO C Fortran)
 # The project version number.
 set(VERSION_MAJOR   2   CACHE STRING "Project major version number.")
 set(VERSION_MINOR   4   CACHE STRING "Project minor version number.")
-set(VERSION_PATCH   0   CACHE STRING "Project patch version number.")
+set(VERSION_PATCH   1   CACHE STRING "Project patch version number.")
 mark_as_advanced(VERSION_MAJOR VERSION_MINOR VERSION_PATCH)
 
 # The size of the data buffer for write/read_darray().