diff --git a/CHANGELOG.md b/CHANGELOG.md
index 05bce7334a..7220a85e1b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## unreleased
 
 * [CHANGE] Make setting out-of-order native histograms feature (`--enable-feature=ooo-native-histograms`) a no-op. Out-of-order native histograms are now always enabled when `out_of_order_time_window` is greater than zero and `--enable-feature=native-histograms` is set. #16207
+* [ENHANCEMENT] TSDB: add `prometheus_tsdb_wal_replay_unknown_refs_total` and `prometheus_tsdb_wbl_replay_unknown_refs_total` metrics to track unknown series references during WAL/WBL replay. #16166
 * [BUGFIX] TSDB: fix unknown series errors and possible lost data during WAL replay when series are removed from the head due to inactivity and reappear before the next WAL checkpoint. #16060
 
 ## 3.2.1 / 2025-02-25