diff --git a/src/common/steamnetworkingsockets_messages_udp.proto b/src/common/steamnetworkingsockets_messages_udp.proto
index f72a45a..bff8916 100644
--- a/src/common/steamnetworkingsockets_messages_udp.proto
+++ b/src/common/steamnetworkingsockets_messages_udp.proto
@@ -137,18 +137,6 @@ message CMsgSteamSockets_UDP_Stats
 	// End to end stats
 	optional CMsgSteamDatagramConnectionQuality stats = 1;
 
-	/// If acks are reasonably rare compared to outgoing data packets,
-	/// we will usually be able to fit an ack in the header of a data packet.
-	/// If we need to send multiple acks, or a standalong stats message,
-	/// we can put them here.
-	///
-	/// Intentionally not array packed, since having more than one is actually
-	/// rare and sending a single value "packed" takes more bytes.
-	/// Upper 16 bits is the sequence number, lower is the delay
-	///
-	/// Note that we really need to integrate this better with the SNP acks/nacks.
-	//repeated fixed32 ack_e2e = 2;
-
 	enum Flags
 	{
 		//ACK_REQUEST_RELAY = 1; // Reserved
@@ -159,15 +147,6 @@ message CMsgSteamSockets_UDP_Stats
 	/// Additional flags.  Should we try to put these in the
 	/// message header and save a few bytes?
 	optional uint32 flags = 3;
-
-	//
-	// Envelope data.  Not present if the message is
-	// inline in a data message
-	//
-	//optional fixed32 legacy_client_connection_id = 8;
-	optional fixed32 to_connection_id = 9;
-	optional fixed32 from_connection_id = 10;
-	optional uint32 seq_num = 4;
 };
 
 // Do not remove this comment due to a bug on the Mac OS X protobuf compiler
diff --git a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_udp.cpp b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_udp.cpp
index 46c6900..1f775b4 100644
--- a/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_udp.cpp
+++ b/src/steamnetworkingsockets/clientlib/steamnetworkingsockets_udp.cpp
@@ -1311,7 +1311,6 @@ void CConnectionTransportUDP::Received_Data( const uint8 *pPkt, int cbPkt, Steam
 		}
 
 		// Shove sequence number so we know what acks to pend, etc
-		msgStats.set_seq_num( nWirePktNumber );
 		pMsgStatsIn = &msgStats;
 
 		// Advance pointer