diff --git a/configure.ac b/configure.ac
index d3f92f4..bd57c43 100644
--- a/configure.ac
+++ b/configure.ac
@@ -125,7 +125,7 @@
 AC_DEFINE(SYSTEMD_INTERFACE, "org.freedesktop.systemd1.Manager", [systemd interface.])
 
 # 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])
 
 # For libtools