diff --git a/configure.ac b/configure.ac
index a6b1453..2f8356b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -21,7 +21,7 @@
 )
 
 # Checks for typedefs, structures, and compiler characteristics.
-AX_CXX_COMPILE_STDCXX(17, [noext], [mandatory])
+AX_CXX_COMPILE_STDCXX(20, [noext], [mandatory])
 AX_APPEND_COMPILE_FLAGS([-fpic -Wall], [CFLAGS])
 AX_APPEND_COMPILE_FLAGS([-fpic -Wall], [CXXFLAGS])