diff --git a/CHANGELOG.md b/CHANGELOG.md
index 417be35..ede2458 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -23,6 +23,30 @@ skip versions are the composition of each intervening adjacent
 release's steps in order — no A-to-B path is pre-computed beyond
 that.
 
+## 0.51.0 — 2026-06-07
+
+**Minor — bulk tag/untag metadata edit (§22.4a SLICE-5).**
+An authorized user can now apply one metadata field change to many catalog
+entries at once. A new endpoint
+`POST /api/projects/{id}/collections/{cid}/meta/bulk` takes
+`{slugs, op: set|add|remove, field, value}`, validates each entry against the
+collection's `fields:` schema at the write boundary (INV-4), writes the passing
+entries' `<slug>.meta.yaml` **sidecars** in a **single commit** (D7: bulk = one
+commit, reusing the SLICE-4 sidecar write-through), re-ingests, and returns
+`{applied, rejected}` so partial failures (missing entry, invalid value) are
+reported without sinking the batch. `set` works for any field; `add`/`remove`
+operate on a `tags`-type field. In the faceted catalog, contributors now get a
+per-row selection checkbox and a sticky bulk action bar (one "Set ▾" control per
+enum field, add/remove-tag for tags fields); a successful apply toasts the
+applied/skipped counts and refreshes the list. This completes PUC-2 of the
+[Configurable Collection Metadata](./docs/design/2026-06-06-configurable-collection-metadata.md)
+design (§5.3, §6.4/§6.5).
+
+No deployment action required. The endpoint and the bulk bar are additive and
+opt-in per collection: a collection with no `fields:` block (INV-5 — the
+default `document` collection) shows no selection UI and the endpoint returns
+`422`, so an N=1 deployment sees zero change.
+
 ## 0.50.0 — 2026-06-07
 
 **Minor — single-entry metadata edit + sidecar-aware writes (§22.4a SLICE-4).**
diff --git a/VERSION b/VERSION
index 564edf8..c5d4cee 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-0.50.0
+0.51.0
diff --git a/frontend/package.json b/frontend/package.json
index 1be35a6..9abf447 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -1,7 +1,7 @@
 {
   "name": "rfc-app-frontend",
   "private": true,
-  "version": "0.50.0",
+  "version": "0.51.0",
   "type": "module",
   "scripts": {
     "dev": "vite",