diff --git a/CMakeLists.txt b/CMakeLists.txt
index 22c5817..145ef8f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,7 +10,7 @@
 ############################################
 
 
-cmake_minimum_required( VERSION 3.1 )
+cmake_minimum_required( VERSION 3.5 )
 
 
 #### general package setup