protocol_type is an array field
@@ -185,7 +185,7 @@ static uint8_t *write_pair_cid_impl(uint8_t *p, const uint8_t *name,
static uint8_t *write_common_fields(uint8_t *p, const ngtcp2_cid *odcid) {
p = write_verbatim(
- p, "\"common_fields\":{\"protocol_type\":\"QUIC\",\"time_format\":"
+ p, "\"common_fields\":{\"protocol_type\":[\"QUIC\"],\"time_format\":"
"\"relative\",\"reference_time\":0,\"group_id\":");
p = write_cid(p, odcid);
*p++ = '}';
