diff --git a/api-outline.md b/api-outline.md
index 2e67be0..98f4e40 100644
--- a/api-outline.md
+++ b/api-outline.md
@@ -126,7 +126,6 @@ interface RtpSendStream {
   readonly attribute DOMString mid?;  // Shared among many RtpSendStreams
   readonly attribute DOMString rid?;  // Unique to RtpSendStream (scoped to MID)
   readonly attribute unsigned long ssrc;
-  readonly attribute unsigned long rtxSsrc;
 
   attribute EventHandler onpacketizedrtp;
   sequence<RtpPacket> readPacketizedRtp(long maxNumberOfPackets);
@@ -166,7 +165,6 @@ interface RtpReceiveStream {
   readonly attribute DOMString mid?;  // Shared among many RtpReceivetreams
   readonly attribute DOMString rid?;  // Unique to RtpReceiveStream (scoped to MID)
   readonly attribute sequence<unsigned long> ssrcs;
-  readonly attribute sequence<unsigned long> rtxSsrcs;
 
   attribute EventHandler onreceivedrtp;
   sequence<RtpPacket> readReceivedRtp(long maxNumberOfPackets);