diff --git a/CMakeLists.txt b/CMakeLists.txt
index 30f2947..597675c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.10)
+cmake_minimum_required(VERSION 3.9)
 project(ghcfilesystem)
 
 if(NOT DEFINED CMAKE_CXX_STANDARD)