--- openvpn-2.4.5/src/openvpn/openssl_compat.h.orig	2018-02-28 21:56:54.000000000 +0100
+++ openvpn-2.4.5/src/openvpn/openssl_compat.h	2018-03-01 11:44:57.000000000 +0100
@@ -672,14 +672,18 @@
     {
         return TLS1_VERSION;
     }
+#ifdef SSL_OP_NO_TLSv1_1
     if (!(sslopt & SSL_OP_NO_TLSv1_1))
     {
         return TLS1_1_VERSION;
     }
+#endif
+#ifdef SSL_OP_NO_TLSv1_2
     if (!(sslopt & SSL_OP_NO_TLSv1_2))
     {
         return TLS1_2_VERSION;
     }
+#endif
     return 0;
 }
 #endif /* SSL_CTX_get_min_proto_version */