diff --git a/src/openssl.hxx b/src/openssl.hxx
index 09fe18f..fc9d8e3 100644
--- a/src/openssl.hxx
+++ b/src/openssl.hxx
@@ -20,7 +20,7 @@
 #include <openssl/opensslv.h>
 #ifndef OPENSSL_VERSION_NUMBER
 #  error OpenSSL Version Number not Found
-#elif OPENSSL_VERSION_NUMBER < 0x01000000L
+#elif OPENSSL_VERSION_NUMBER < 0x10000000L
 #  define OPENSSL_0
 #  define V0_CONST const
 #else