diff --git a/changes/unreleased/20260916-v3-benchmark-dashboard.yaml b/changes/unreleased/20260916-v3-benchmark-dashboard.yaml
new file mode 100644
index 0000000..5efe25d
--- /dev/null
+++ b/changes/unreleased/20260916-v3-benchmark-dashboard.yaml
@@ -0,0 +1,5 @@
+kind: Added
+body: 'Added a V3 benchmark dashboard and validation reports covering Redis and Valkey performance at up to one million keywords.'
+time: 2026-09-16T00:00:00+09:00
+custom:
+  Issue: "256"
diff --git a/changes/unreleased/20260916-v3-search-staging-optimization.yaml b/changes/unreleased/20260916-v3-search-staging-optimization.yaml
new file mode 100644
index 0000000..6e921c1
--- /dev/null
+++ b/changes/unreleased/20260916-v3-search-staging-optimization.yaml
@@ -0,0 +1,5 @@
+kind: Changed
+body: 'Optimized V3 search scanning and batched Redis staging to reduce work for common ASCII inputs and multi-bucket updates.'
+time: 2026-09-16T00:00:00+09:00
+custom:
+  Issue: "259"
diff --git a/changes/unreleased/20260916-v3-single-serving-engine.yaml b/changes/unreleased/20260916-v3-single-serving-engine.yaml
new file mode 100644
index 0000000..de73f2c
--- /dev/null
+++ b/changes/unreleased/20260916-v3-single-serving-engine.yaml
@@ -0,0 +1,5 @@
+kind: Changed
+body: 'V3 now serves one immutable engine for every version, removing the experimental two-automaton overlay while retaining DeltaSearch option and status compatibility.'
+time: 2026-09-16T00:00:00+09:00
+custom:
+  Issue: "260"