diff --git a/docs/CMakeLists.txt b/docs/CMakeLists.txt
index eb17631..7b8eef9 100644
--- a/docs/CMakeLists.txt
+++ b/docs/CMakeLists.txt
@@ -5,7 +5,7 @@
 #
 #-------------------------------------------------------------------------------
 
-cmake_minimum_required(VERSION 3.15)
+cmake_minimum_required(VERSION 3.21)
 
 add_custom_target(docs)