diff --git a/src/core/core-url.c b/src/core/core-url.c
index 2b360d578..f82ec477e 100644
--- a/src/core/core-url.c
+++ b/src/core/core-url.c
@@ -89,12 +89,14 @@ 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),