diff --git a/quic/core/quic_flags_list.h b/quic/core/quic_flags_list.h
index 6888141..3b264f5 100644
--- a/quic/core/quic_flags_list.h
+++ b/quic/core/quic_flags_list.h
@@ -65,7 +65,7 @@
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_tls_use_early_select_cert, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_tls_use_per_handshaker_proof_source, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_unified_iw_options, false)
-QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_use_circular_deque_for_unacked_packets_v2, false)
+QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_use_circular_deque_for_unacked_packets_v2, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_use_encryption_level_context, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_use_write_or_buffer_data_at_level, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_send_quic_fallback_server_config_on_leto_error, false)