diff --git a/modules/rtp_rtcp/include/rtp_rtcp_defines.h b/modules/rtp_rtcp/include/rtp_rtcp_defines.h
index 8232898..03dcda3 100644
--- a/modules/rtp_rtcp/include/rtp_rtcp_defines.h
+++ b/modules/rtp_rtcp/include/rtp_rtcp_defines.h
@@ -55,6 +55,7 @@
   kRtpExtensionAbsoluteSendTime,
   kRtpExtensionVideoRotation,
   kRtpExtensionTransportSequenceNumber,
+  kRtpExtensionTransportSequenceNumber02,
   kRtpExtensionPlayoutDelay,
   kRtpExtensionVideoContentType,
   kRtpExtensionVideoTiming,
diff --git a/modules/rtp_rtcp/source/rtp_header_extension_map.cc b/modules/rtp_rtcp/source/rtp_header_extension_map.cc
index 4eec8d3..b4aaf3f 100644
--- a/modules/rtp_rtcp/source/rtp_header_extension_map.cc
+++ b/modules/rtp_rtcp/source/rtp_header_extension_map.cc
@@ -35,6 +35,7 @@
     CreateExtensionInfo<AbsoluteSendTime>(),
     CreateExtensionInfo<VideoOrientation>(),
     CreateExtensionInfo<TransportSequenceNumber>(),
+    CreateExtensionInfo<TransportSequenceNumberV2>(),
     CreateExtensionInfo<PlayoutDelayLimits>(),
     CreateExtensionInfo<VideoContentTypeExtension>(),
     CreateExtensionInfo<VideoTimingExtension>(),
diff --git a/modules/rtp_rtcp/source/rtp_header_extensions.cc b/modules/rtp_rtcp/source/rtp_header_extensions.cc
index 38c2d5a..e531a88 100644
--- a/modules/rtp_rtcp/source/rtp_header_extensions.cc
+++ b/modules/rtp_rtcp/source/rtp_header_extensions.cc
@@ -126,27 +126,93 @@
   return true;
 }
 
+// TransportSequenceNumber
+//
 //   0                   1                   2
 //   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3
 //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-//  |  ID   | L=1   |transport wide sequence number |
+//  |  ID   | L=1   |transport-wide sequence number |
 //  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 constexpr RTPExtensionType TransportSequenceNumber::kId;
 constexpr uint8_t TransportSequenceNumber::kValueSizeBytes;
 constexpr const char TransportSequenceNumber::kUri[];
 
 bool TransportSequenceNumber::Parse(rtc::ArrayView<const uint8_t> data,
-                                    uint16_t* value) {
-  if (data.size() != 2)
+                                    uint16_t* transport_sequence_number) {
+  if (data.size() != kValueSizeBytes)
     return false;
-  *value = ByteReader<uint16_t>::ReadBigEndian(data.data());
+  *transport_sequence_number = ByteReader<uint16_t>::ReadBigEndian(data.data());
   return true;
 }
 
 bool TransportSequenceNumber::Write(rtc::ArrayView<uint8_t> data,
-                                    uint16_t value) {
-  RTC_DCHECK_EQ(data.size(), 2);
-  ByteWriter<uint16_t>::WriteBigEndian(data.data(), value);
+                                    uint16_t transport_sequence_number) {
+  RTC_DCHECK_EQ(data.size(), ValueSize(transport_sequence_number));
+  ByteWriter<uint16_t>::WriteBigEndian(data.data(), transport_sequence_number);
+  return true;
+}
+
+// TransportSequenceNumberV2
+//
+// In addition to the format used for TransportSequencNumber, V2 also supports
+// the following packet format where two extra bytes are used to specify that
+// the sender requests immediate feedback.
+//   0                   1                   2                   3
+//   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//  |  ID   | L=3   |transport-wide sequence number |T|  seq count  |
+//  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+//  |seq count cont.|
+//  +-+-+-+-+-+-+-+-+
+//
+// The bit |T| determines whether the feedback should include timing information
+// or not and |seq_count| determines how many additional packets the feedback
+// packet should cover.
+constexpr RTPExtensionType TransportSequenceNumberV2::kId;
+constexpr uint8_t TransportSequenceNumberV2::kValueSizeBytesWithFeedbackRequest;
+constexpr const char TransportSequenceNumberV2::kUri[];
+constexpr uint16_t TransportSequenceNumberV2::kIncludeTimestampsBit;
+
+bool TransportSequenceNumberV2::Parse(
+    rtc::ArrayView<const uint8_t> data,
+    uint16_t* transport_sequence_number,
+    absl::optional<FeedbackRequest>* feedback_request) {
+  if (data.size() != TransportSequenceNumber::kValueSizeBytes &&
+      data.size() != kValueSizeBytesWithFeedbackRequest)
+    return false;
+
+  *transport_sequence_number = ByteReader<uint16_t>::ReadBigEndian(data.data());
+
+  if (data.size() == kValueSizeBytesWithFeedbackRequest) {
+    uint16_t feedback_request_raw =
+        ByteReader<uint16_t>::ReadBigEndian(data.data() + 2);
+    bool include_timestamps =
+        (feedback_request_raw & kIncludeTimestampsBit) != 0;
+    uint16_t sequence_count = feedback_request_raw & ~kIncludeTimestampsBit;
+    *feedback_request = {include_timestamps, sequence_count};
+  } else {
+    *feedback_request = absl::nullopt;
+  }
+  return true;
+}
+
+bool TransportSequenceNumberV2::Write(
+    rtc::ArrayView<uint8_t> data,
+    uint16_t transport_sequence_number,
+    const absl::optional<FeedbackRequest>& feedback_request) {
+  RTC_DCHECK_EQ(data.size(),
+                ValueSize(transport_sequence_number, feedback_request));
+
+  ByteWriter<uint16_t>::WriteBigEndian(data.data(), transport_sequence_number);
+
+  if (feedback_request) {
+    RTC_DCHECK_GE(feedback_request->sequence_count, 0);
+    RTC_DCHECK_LT(feedback_request->sequence_count, kIncludeTimestampsBit);
+    uint16_t feedback_request_raw =
+        feedback_request->sequence_count |
+        (feedback_request->include_timestamps ? kIncludeTimestampsBit : 0);
+    ByteWriter<uint16_t>::WriteBigEndian(data.data() + 2, feedback_request_raw);
+  }
   return true;
 }
 
diff --git a/modules/rtp_rtcp/source/rtp_header_extensions.h b/modules/rtp_rtcp/source/rtp_header_extensions.h
index 9f4a28b..e37388a 100644
--- a/modules/rtp_rtcp/source/rtp_header_extensions.h
+++ b/modules/rtp_rtcp/source/rtp_header_extensions.h
@@ -81,9 +81,38 @@
   static constexpr const char kUri[] =
       "http://www.ietf.org/id/"
       "draft-holmer-rmcat-transport-wide-cc-extensions-01";
-  static bool Parse(rtc::ArrayView<const uint8_t> data, uint16_t* value);
-  static size_t ValueSize(uint16_t value) { return kValueSizeBytes; }
-  static bool Write(rtc::ArrayView<uint8_t> data, uint16_t value);
+  static bool Parse(rtc::ArrayView<const uint8_t> data,
+                    uint16_t* transport_sequence_number);
+  static size_t ValueSize(uint16_t /*transport_sequence_number*/) {
+    return kValueSizeBytes;
+  }
+  static bool Write(rtc::ArrayView<uint8_t> data,
+                    uint16_t transport_sequence_number);
+};
+
+class TransportSequenceNumberV2 {
+ public:
+  static constexpr RTPExtensionType kId =
+      kRtpExtensionTransportSequenceNumber02;
+  static constexpr uint8_t kValueSizeBytesWithFeedbackRequest = 4;
+  static constexpr const char kUri[] =
+      "http://www.ietf.org/id/"
+      "draft-holmer-rmcat-transport-wide-cc-extensions-02";
+  static bool Parse(rtc::ArrayView<const uint8_t> data,
+                    uint16_t* transport_sequence_number,
+                    absl::optional<FeedbackRequest>* feedback_request);
+  static size_t ValueSize(
+      uint16_t /*transport_sequence_number*/,
+      const absl::optional<FeedbackRequest>& feedback_request) {
+    return feedback_request ? kValueSizeBytesWithFeedbackRequest
+                            : TransportSequenceNumber::kValueSizeBytes;
+  }
+  static bool Write(rtc::ArrayView<uint8_t> data,
+                    uint16_t transport_sequence_number,
+                    const absl::optional<FeedbackRequest>& feedback_request);
+
+ private:
+  static constexpr uint16_t kIncludeTimestampsBit = 1 << 15;
 };
 
 class VideoOrientation {
diff --git a/modules/rtp_rtcp/source/rtp_packet_received.cc b/modules/rtp_rtcp/source/rtp_packet_received.cc
index f80fad6..2a36b7b 100644
--- a/modules/rtp_rtcp/source/rtp_packet_received.cc
+++ b/modules/rtp_rtcp/source/rtp_packet_received.cc
@@ -52,6 +52,9 @@
   header->extension.hasAbsoluteSendTime =
       GetExtension<AbsoluteSendTime>(&header->extension.absoluteSendTime);
   header->extension.hasTransportSequenceNumber =
+      GetExtension<TransportSequenceNumberV2>(
+          &header->extension.transportSequenceNumber,
+          &header->extension.feedback_request) ||
       GetExtension<TransportSequenceNumber>(
           &header->extension.transportSequenceNumber);
   header->extension.hasAudioLevel = GetExtension<AudioLevel>(
diff --git a/modules/rtp_rtcp/source/rtp_packet_unittest.cc b/modules/rtp_rtcp/source/rtp_packet_unittest.cc
index 0d24272..4700a77 100644
--- a/modules/rtp_rtcp/source/rtp_packet_unittest.cc
+++ b/modules/rtp_rtcp/source/rtp_packet_unittest.cc
@@ -827,4 +827,62 @@
   TestCreateAndParseColorSpaceExtension(/*with_hdr_metadata=*/false);
 }
 
+TEST(RtpPacketTest, CreateAndParseTransportSequenceNumber) {
+  // Create a packet with transport sequence number extension populated.
+  RtpPacketToSend::ExtensionManager extensions;
+  constexpr int kExtensionId = 1;
+  extensions.Register<TransportSequenceNumber>(kExtensionId);
+  RtpPacketToSend send_packet(&extensions);
+  send_packet.SetPayloadType(kPayloadType);
+  send_packet.SetSequenceNumber(kSeqNum);
+  send_packet.SetTimestamp(kTimestamp);
+  send_packet.SetSsrc(kSsrc);
+
+  constexpr int kTransportSequenceNumber = 12345;
+  send_packet.SetExtension<TransportSequenceNumber>(kTransportSequenceNumber);
+
+  // Serialize the packet and then parse it again.
+  RtpPacketReceived receive_packet(&extensions);
+  EXPECT_TRUE(receive_packet.Parse(send_packet.Buffer()));
+
+  uint16_t received_transport_sequeunce_number;
+  EXPECT_TRUE(receive_packet.GetExtension<TransportSequenceNumber>(
+      &received_transport_sequeunce_number));
+  EXPECT_EQ(received_transport_sequeunce_number, kTransportSequenceNumber);
+}
+
+TEST(RtpPacketTest, CreateAndParseTransportSequenceNumberWithFeedbackRequest) {
+  // Create a packet with TransportSequenceNumberV2 extension populated.
+  RtpPacketToSend::ExtensionManager extensions;
+  constexpr int kExtensionId = 1;
+  extensions.Register<TransportSequenceNumberV2>(kExtensionId);
+  RtpPacketToSend send_packet(&extensions);
+  send_packet.SetPayloadType(kPayloadType);
+  send_packet.SetSequenceNumber(kSeqNum);
+  send_packet.SetTimestamp(kTimestamp);
+  send_packet.SetSsrc(kSsrc);
+
+  constexpr int kTransportSequenceNumber = 12345;
+  constexpr absl::optional<FeedbackRequest> kFeedbackRequest =
+      FeedbackRequest{/*include_timestamps=*/true, /*sequence_count=*/3};
+  send_packet.SetExtension<TransportSequenceNumberV2>(kTransportSequenceNumber,
+                                                      kFeedbackRequest);
+
+  // Serialize the packet and then parse it again.
+  RtpPacketReceived receive_packet(&extensions);
+  EXPECT_TRUE(receive_packet.Parse(send_packet.Buffer()));
+
+  // Parse transport sequence number and feedback request.
+  uint16_t received_transport_sequeunce_number;
+  absl::optional<FeedbackRequest> received_feedback_request;
+  EXPECT_TRUE(receive_packet.GetExtension<TransportSequenceNumberV2>(
+      &received_transport_sequeunce_number, &received_feedback_request));
+  EXPECT_EQ(received_transport_sequeunce_number, kTransportSequenceNumber);
+  ASSERT_TRUE(received_feedback_request);
+  EXPECT_EQ(received_feedback_request->include_timestamps,
+            kFeedbackRequest->include_timestamps);
+  EXPECT_EQ(received_feedback_request->sequence_count,
+            kFeedbackRequest->sequence_count);
+}
+
 }  // namespace webrtc
diff --git a/modules/rtp_rtcp/source/rtp_utility.cc b/modules/rtp_rtcp/source/rtp_utility.cc
index 1203823..8811bf1 100644
--- a/modules/rtp_rtcp/source/rtp_utility.cc
+++ b/modules/rtp_rtcp/source/rtp_utility.cc
@@ -433,6 +433,10 @@
           header->extension.hasTransportSequenceNumber = true;
           break;
         }
+        case kRtpExtensionTransportSequenceNumber02:
+          RTC_LOG(WARNING) << "TransportSequenceNumberV2 unsupported by rtp "
+                              "header parser.";
+          break;
         case kRtpExtensionPlayoutDelay: {
           if (len != 2) {
             RTC_LOG(LS_WARNING) << "Incorrect playout delay len: " << len;
diff --git a/test/fuzzers/BUILD.gn b/test/fuzzers/BUILD.gn
index 797c27d..6e723e1 100644
--- a/test/fuzzers/BUILD.gn
+++ b/test/fuzzers/BUILD.gn
@@ -230,6 +230,7 @@
   ]
   deps = [
     "../../modules/rtp_rtcp:rtp_rtcp_format",
+    "//third_party/abseil-cpp/absl/types:optional",
   ]
   seed_corpus = "corpora/rtp-corpus"
 }
diff --git a/test/fuzzers/rtp_packet_fuzzer.cc b/test/fuzzers/rtp_packet_fuzzer.cc
index d2de72d..730124c 100644
--- a/test/fuzzers/rtp_packet_fuzzer.cc
+++ b/test/fuzzers/rtp_packet_fuzzer.cc
@@ -10,6 +10,7 @@
 
 #include <bitset>
 
+#include "absl/types/optional.h"
 #include "modules/rtp_rtcp/include/rtp_header_extension_map.h"
 #include "modules/rtp_rtcp/source/rtp_generic_frame_descriptor_extension.h"
 #include "modules/rtp_rtcp/source/rtp_header_extensions.h"
@@ -86,6 +87,13 @@
         uint16_t seqnum;
         packet.GetExtension<TransportSequenceNumber>(&seqnum);
         break;
+      case kRtpExtensionTransportSequenceNumber02: {
+        uint16_t seqnum;
+        absl::optional<FeedbackRequest> feedback_request;
+        packet.GetExtension<TransportSequenceNumberV2>(&seqnum,
+                                                       &feedback_request);
+        break;
+      }
       case kRtpExtensionPlayoutDelay:
         PlayoutDelay playout;
         packet.GetExtension<PlayoutDelayLimits>(&playout);