diff --git a/src/core/core-url.c b/src/core/core-url.c
index ff2e54976..f3d432ef1 100644
--- a/src/core/core-url.c
+++ b/src/core/core-url.c
@@ -88,12 +88,14 @@ struct t_url_constant url_protocols[] =
     URL_DEF_CONST(PROTO, SMTP),
     URL_DEF_CONST(PROTO, SMTPS),
     URL_DEF_CONST(PROTO, RTSP),
+#if LIBCURL_VERSION_NUM < 0x081400 /* < 8.20.0 */
     URL_DEF_CONST(PROTO, RTMP),
     URL_DEF_CONST(PROTO, RTMPT),
     URL_DEF_CONST(PROTO, RTMPE),
     URL_DEF_CONST(PROTO, RTMPTE),
     URL_DEF_CONST(PROTO, RTMPS),
     URL_DEF_CONST(PROTO, RTMPTS),
+#endif
     URL_DEF_CONST(PROTO, GOPHER),
     URL_DEF_CONST(PROTO, SMB),
     URL_DEF_CONST(PROTO, SMBS),
@@ -122,7 +124,9 @@ struct t_url_constant url_auth[] =
     URL_DEF_CONST(AUTH, NTLM),
     URL_DEF_CONST(AUTH, ANY),
     URL_DEF_CONST(AUTH, ANYSAFE),
+#if LIBCURL_VERSION_NUM < 0x081500 /* < 8.21.0 */
     URL_DEF_CONST(AUTH, DIGEST_IE),
+#endif
     URL_DEF_CONST(AUTH, ONLY),
 #if LIBCURL_VERSION_NUM < 0x080800 /* < 8.8.0 */
     URL_DEF_CONST(AUTH, NTLM_WB),
@@ -651,7 +655,9 @@ struct t_url_option url_options[] =
     URL_DEF_OPTION(SSLENGINE_DEFAULT, LONG, NULL),
     URL_DEF_OPTION(CAPATH, STRING, NULL),
     URL_DEF_OPTION(SSL_SESSIONID_CACHE, LONG, NULL),
+#if LIBCURL_VERSION_NUM < 0x081100 /* < 8.17.0 */
     URL_DEF_OPTION(KRBLEVEL, STRING, NULL),
+#endif
     URL_DEF_OPTION(KEYPASSWD, STRING, NULL),
     URL_DEF_OPTION(ISSUERCERT, STRING, NULL),
     URL_DEF_OPTION(CRLFILE, STRING, NULL),