diff --git a/quiche/common/quiche_feature_flags_list.h b/quiche/common/quiche_feature_flags_list.h
index eb4aecc..99029f0 100755
--- a/quiche/common/quiche_feature_flags_list.h
+++ b/quiche/common/quiche_feature_flags_list.h
@@ -37,7 +37,7 @@
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_enobufs_blocked, false, false, "If true, ENOBUFS socket errors are reported as socket blocked instead of socket failure.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_fin_before_completed_http_headers, false, true, "If true, close the connection with error if FIN is received before finish receiving the whole HTTP headers.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_fix_timeouts, true, true, "If true, postpone setting handshake timeout to infinite to handshake complete.")
-QUICHE_FLAG(bool, quiche_reloadable_flag_quic_heapless_key_derivation, false, true, "If true, QUIC key derivation uses heapless crypto utils.")
+QUICHE_FLAG(bool, quiche_reloadable_flag_quic_heapless_key_derivation, true, true, "If true, QUIC key derivation uses heapless crypto utils.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_heapless_static_parser, true, true, "If true, stops parsing immediately on unknown version, to avoid a potential malloc when parsing the connection ID")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_ignore_gquic_probing, true, true, "If true, QUIC server will not respond to gQUIC probing packet(PING + PADDING) but treat it as a regular packet.")
 QUICHE_FLAG(bool, quiche_reloadable_flag_quic_least_unacked_plus_1, false, false, "If true, sets peer_least_packet_awaiting_ack to one more than the highest confirmed acknowledgment to fix an off-by-one error.")