diff --git a/CMakeLists.txt b/CMakeLists.txt
index 59e24877..efb2c5b7 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -138,6 +138,8 @@ endif()
 if ("${CMAKE_CXX14_STANDARD_COMPILE_OPTION}" STREQUAL "-std=c++1y")
   set(CMAKE_CXX_STANDARD 11)
 endif()
+# temporarily
+set(CMAKE_CXX_STANDARD 17)
 
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_CXX_EXTENSIONS OFF)