diff --git a/config.h b/config.h
index d73e2372..c82f7021 100644
--- a/config.h
+++ b/config.h
@@ -237,7 +237,7 @@ typedef unsigned int word32;
 #if defined(_MSC_VER) || defined(__BORLANDC__)
 	typedef unsigned __int64 word64;
 	#define W64LIT(x) x##ui64
-#elif (_LP64 || __LP64__) && ((__arm64__ || __aarch64__) || !defined(CRYPTOPP_MAINTAIN_BACKWARDS_COMPATIBILITY_562))
+#elif (_LP64 || __LP64__)
 	typedef unsigned long word64;
 	#define W64LIT(x) x##UL
 #else