diff --git a/logging/rtc_event_log/rtc_event_log_parser_new.cc b/logging/rtc_event_log/rtc_event_log_parser_new.cc
index 7ae7fefe58..7926f3bf9c 100644
--- a/logging/rtc_event_log/rtc_event_log_parser_new.cc
+++ b/logging/rtc_event_log/rtc_event_log_parser_new.cc
@@ -2428,8 +2428,10 @@ void ParsedRtcEventLogNew::StoreIceCandidateEvent(
   ice_event.type = GetRuntimeIceCandidatePairEventType(proto.event_type());
   RTC_CHECK(proto.has_candidate_pair_id());
   ice_event.candidate_pair_id = proto.candidate_pair_id();
-  RTC_CHECK(proto.has_transaction_id());
-  ice_event.transaction_id = proto.transaction_id();
+  // TODO(zstein): Make the transaction_id field required once all old versions
+  // of the log (which don't have the field) are obsolete.
+  if (proto.has_transaction_id())
+    ice_event.transaction_id = proto.transaction_id();
 
   ice_candidate_pair_events_.push_back(ice_event);