Picked 3.31 just because it is the oldest dev-build/cmake in ::gentoo as of 2025-11-19.

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9487ab98a594..a9219cd2cf39 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -3,7 +3,7 @@
 # Modifications Copyright (C) 2019 Matthias C. Hormann <mhormann@gmx.de>
 # This file is released under the 2 clause BSD license, see COPYING
 
-CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
+CMAKE_MINIMUM_REQUIRED(VERSION 3.31)
 PROJECT(loudgain C CXX)
 
 SET(CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake/" ${CMAKE_MODULE_PATH})