diff --git a/connect.c b/connect.c
index 70b13389ba..aff13a270e 100644
--- a/connect.c
+++ b/connect.c
@@ -164,6 +164,8 @@ enum protocol_version discover_version(struct packet_reader *reader)
 		BUG("unknown protocol version");
 	}
 
+	trace2_data_intmax("transfer", NULL, "negotiated-version", version);
+
 	return version;
 }
 
diff --git a/protocol.c b/protocol.c
index 052d7edbb9..c53f7df5be 100644
--- a/protocol.c
+++ b/protocol.c
@@ -73,6 +73,8 @@ enum protocol_version determine_protocol_version_server(void)
 		string_list_clear(&list, 0);
 	}
 
+	trace2_data_intmax("transfer", NULL, "negotiated-version", version);
+
 	return version;
 }
 
diff --git a/t/t5705-session-id-in-capabilities.sh b/t/t5705-session-id-in-capabilities.sh
index f1d189d5bc..eb8c79aafd 100755
--- a/t/t5705-session-id-in-capabilities.sh
+++ b/t/t5705-session-id-in-capabilities.sh
@@ -73,6 +73,17 @@ do
 		grep \"key\":\"server-sid\" tr2-client-events &&
 		grep \"key\":\"client-sid\" tr2-server-events
 	'
+
+	test_expect_success "client & server log negotiated version (v${PROTO})" '
+		test_when_finished "rm -rf local tr2-client-events tr2-server-events" &&
+		cp -r "$LOCAL_PRISTINE" local &&
+		GIT_TRACE2_EVENT="$(pwd)/tr2-client-events" \
+		git -c protocol.version=$PROTO -C local fetch \
+			--upload-pack "GIT_TRACE2_EVENT=\"$(pwd)/tr2-server-events\" git-upload-pack" \
+			origin &&
+		grep \"key\":\"negotiated-version\",\"value\":\"$PROTO\" tr2-client-events &&
+		grep \"key\":\"negotiated-version\",\"value\":\"$PROTO\" tr2-server-events
+	'
 done
 
 test_done