diff --git a/CMakeLists.txt b/CMakeLists.txt
index 421ce0f..b2fe617 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,7 +2,7 @@
 # This file is subject to the license terms in the LICENSE file
 # found in the top-level directory of this distribution.
 
-cmake_minimum_required(VERSION 3.5)
+cmake_minimum_required(VERSION 4.0)
 
 project(TYPE_SAFE)
 
diff --git a/external/debug_assert/CMakeLists.txt b/external/debug_assert/CMakeLists.txt
index f9adcfc..fe33dea 100644
--- a/external/debug_assert/CMakeLists.txt
+++ b/external/debug_assert/CMakeLists.txt
@@ -2,7 +2,7 @@
 # This file is subject to the license terms in the LICENSE file
 # found in the top-level directory of this distribution.
 
-cmake_minimum_required(VERSION 3.5)
+cmake_minimum_required(VERSION 4.0)
 project(DEBUG_ASSERT)
 
 # Determine if debug_assert is built as a subproject (using add_subdirectory)