diff --git a/quic/core/quic_flags_list.h b/quic/core/quic_flags_list.h
index 42574c8..e76c6e3 100644
--- a/quic/core/quic_flags_list.h
+++ b/quic/core/quic_flags_list.h
@@ -58,7 +58,7 @@
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_send_timestamps, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_send_tls_crypto_error_code, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_send_version_negotiation_for_short_connection_ids, true)
-QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_single_ack_in_packet2, false)
+QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_single_ack_in_packet2, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_split_up_send_rst_2, true)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_start_peer_migration_earlier, false)
 QUIC_FLAG(FLAGS_quic_reloadable_flag_quic_testonly_default_false, false)