diff --git a/.changeset/add-graph-follow-lexicon.md b/.changeset/add-graph-follow-lexicon.md
deleted file mode 100644
index 5f86d742..00000000
--- a/.changeset/add-graph-follow-lexicon.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-"@hypercerts-org/lexicon": minor
----
-
-Add `app.certified.graph.follow` lexicon — a social-graph follow record schema-compatible with `app.bsky.graph.follow` (same `tid` key, same `subject` / `createdAt` / optional `via` strongRef fields). Exports new `GRAPH_FOLLOW_NSID`, `GRAPH_FOLLOW_LEXICON_JSON`, `GRAPH_FOLLOW_LEXICON_DOC`, and `AppCertifiedGraphFollow` type namespace.
diff --git a/.changeset/clarify-knownvalues-open-vocabulary.md b/.changeset/clarify-knownvalues-open-vocabulary.md
deleted file mode 100644
index 8ebb5d8e..00000000
--- a/.changeset/clarify-knownvalues-open-vocabulary.md
+++ /dev/null
@@ -1,5 +0,0 @@
----
-"@hypercerts-org/lexicon": patch
----
-
-Clarify that `knownValues` is an open vocabulary, not a closed enum. Adds a "Schema Conventions" section to README.md explaining that custom string values are permitted on any `knownValues` field (and contrasting with `enum`, which is closed and validator-enforced). Updates inline descriptions on `app.certified.location#locationType`, `org.hypercerts.workscope.tag#category`, and `org.hypercerts.workscope.tag#status` to explicitly note that values beyond the listed set are permitted — bringing them in line with the existing wording on `org.hypercerts.collection#type`, `org.hypercerts.context.attachment#contentType`, and `app.certified.badge.definition#badgeType`. The `locationType` description now also explicitly calls out that polygons / multipolygons / featurecollections use the catch-all `geojson` entry rather than a typed variant. Fixes a misleading line in STRING_CONSTRAINTS.md that conflated `knownValues` with `enum`. Documentation-only — no schema or type changes.
diff --git a/CHANGELOG.md b/CHANGELOG.md
index e24bd3b4..958ceaca 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,58 @@
 # @hypercerts-org/lexicon
 
+## 0.13.0
+
+### Minor Changes
+
+- [#209](https://github.com/hypercerts-org/hypercerts-lexicon/pull/209) [`8ec051f`](https://github.com/hypercerts-org/hypercerts-lexicon/commit/8ec051faaf46b507409d97ca609b05fb8f318a3d) Thanks [@s-adamantine](https://github.com/s-adamantine)! - Add `app.certified.graph.follow` lexicon — a social-graph follow record schema-compatible with `app.bsky.graph.follow` (same `tid` key, same `subject` / `createdAt` / optional `via` strongRef fields). Exports new `GRAPH_FOLLOW_NSID`, `GRAPH_FOLLOW_LEXICON_JSON`, `GRAPH_FOLLOW_LEXICON_DOC`, and `AppCertifiedGraphFollow` type namespace.
+
+- [#170](https://github.com/hypercerts-org/hypercerts-lexicon/pull/170) [`97981bd`](https://github.com/hypercerts-org/hypercerts-lexicon/commit/97981bd1d321cb6147c01039103984eb297ebb08) Thanks [@satyam-mishra-pce](https://github.com/satyam-mishra-pce)! - Add cryptographic signature support to all lexicons
+
+  Adds optional cryptographic signature support to all record lexicons, enabling platform attestation and verification that records were created through trusted services. The on-the-wire shape, signing procedure, and verification procedure all conform to Nick Gerakines' [ATProtocol Attestation Specification](https://tangled.org/strings/did:plc:cbkjy5n7bk3ax2wplmtjofq2/3m3fy2xuahc22) (see also the [accompanying blog post](https://ngerakines.leaflet.pub/3m3idxul5hc2r)).
+
+  **New lexicons:**
+  - `app.certified.signature.defs` - Shared type definitions for signatures. Provides:
+    - `#list` - open union array of inline signatures and `com.atproto.repo.strongRef` references to remote proofs
+    - `#inline` - inline signature object with two required fields: `signature` (ECDSA bytes, low-S per BIP-0062, signing the record's CID) and `key` (DID verification method reference). The signing curve is determined by the multicodec prefix on the verification method's `publicKeyMultibase`, so no separate algorithm-tag field is carried on the signature itself.
+  - `app.certified.signature.proof` - Remote attestation proof record containing the CID of the attested content (computed with the spec's `$sig`-repository binding).
+
+  **Changes to existing lexicons:**
+
+  All 21 record lexicons now include an optional `signatures` property (a ref to `app.certified.signature.defs#list`) placed directly on the record with no wrapper object:
+  - `org.hypercerts.claim.activity`
+  - `org.hypercerts.claim.contribution`
+  - `org.hypercerts.claim.contributorInformation`
+  - `org.hypercerts.claim.rights`
+  - `org.hypercerts.collection`
+  - `org.hypercerts.context.acknowledgement`
+  - `org.hypercerts.context.attachment`
+  - `org.hypercerts.context.evaluation`
+  - `org.hypercerts.context.measurement`
+  - `org.hypercerts.funding.receipt`
+  - `org.hypercerts.workscope.tag`
+  - `org.hyperboards.board`
+  - `org.hyperboards.displayProfile`
+  - `app.certified.badge.award`
+  - `app.certified.badge.definition`
+  - `app.certified.badge.response`
+  - `app.certified.actor.profile`
+  - `app.certified.actor.organization`
+  - `app.certified.location`
+  - `app.certified.graph.follow`
+  - `app.certified.link.evm`
+
+  Note on `app.certified.link.evm`: this record carries two orthogonal integrity primitives. The EIP-712 `proof` field proves wallet consent (the EVM key holder agreed to be linked to the DID). The `signatures` array proves record provenance (e.g. that a platform UI minted the record, defending against replay of harvested EIP-712 signatures). Both are useful and they do not conflict.
+
+  **Design notes:**
+
+  This is a non-breaking extension - signatures are optional on all records. Two signature patterns are supported:
+  1. **Inline signatures** - Embedded directly in the record via `app.certified.signature.defs#inline`.
+  2. **Remote attestations** - References to proof records in other repositories via `com.atproto.repo.strongRef`.
+
+### Patch Changes
+
+- [#213](https://github.com/hypercerts-org/hypercerts-lexicon/pull/213) [`80e5b42`](https://github.com/hypercerts-org/hypercerts-lexicon/commit/80e5b427b1e6886417d2db12017e7aa4a42a6482) Thanks [@s-adamantine](https://github.com/s-adamantine)! - Clarify that `knownValues` is an open vocabulary, not a closed enum. Adds a "Schema Conventions" section to README.md explaining that custom string values are permitted on any `knownValues` field (and contrasting with `enum`, which is closed and validator-enforced). Updates inline descriptions on `app.certified.location#locationType`, `org.hypercerts.workscope.tag#category`, and `org.hypercerts.workscope.tag#status` to explicitly note that values beyond the listed set are permitted — bringing them in line with the existing wording on `org.hypercerts.collection#type`, `org.hypercerts.context.attachment#contentType`, and `app.certified.badge.definition#badgeType`. The `locationType` description now also explicitly calls out that polygons / multipolygons / featurecollections use the catch-all `geojson` entry rather than a typed variant. Fixes a misleading line in STRING_CONSTRAINTS.md that conflated `knownValues` with `enum`. Documentation-only — no schema or type changes.
+
 ## 0.12.0
 
 ### Minor Changes
diff --git a/package-lock.json b/package-lock.json
index f0079887..55fd20de 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@hypercerts-org/lexicon",
-  "version": "0.12.0",
+  "version": "0.13.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@hypercerts-org/lexicon",
-      "version": "0.12.0",
+      "version": "0.13.0",
       "license": "MIT",
       "dependencies": {
         "@atproto/lexicon": "^0.6.0",
diff --git a/package.json b/package.json
index 3460ea83..e3911af3 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@hypercerts-org/lexicon",
-  "version": "0.12.0",
+  "version": "0.13.0",
   "description": "ATProto lexicon definitions and TypeScript types for the Hypercerts protocol",
   "type": "module",
   "main": "./dist/index.cjs",