diff --git a/src/cfg.c b/src/cfg.c
index 36582f7b..1b175096 100644
--- a/src/cfg.c
+++ b/src/cfg.c
@@ -152,7 +152,7 @@ int get_tls_protocol_number(char *protocol){
       { "TLSv1", TLS1_VERSION },
       { "TLSv1.1", TLS1_1_VERSION },
       { "TLSv1.2", TLS1_2_VERSION },
-   #if OPENSSL_VERSION_NUMBER >= 0x10100000L
+   #ifdef TLS1_3_VERSION
       { "TLSv1.3", TLS1_3_VERSION },
    #endif
    };