diff --git a/configure.ac b/configure.ac
index 17fc87f..b55685a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -21,7 +21,7 @@
                 [AC_MSG_ERROR([Could not find cereal/archives/binary.hpp... cereal package required])])
 
 # Checks for typedefs, structures, and compiler characteristics.
-AX_CXX_COMPILE_STDCXX_17([noext])
+AX_CXX_COMPILE_STDCXX([20],[noext])
 AX_APPEND_COMPILE_FLAGS([-Wall -Werror], [CXXFLAGS])
 
 LT_INIT