diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..0fa3079
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,38 @@
+# Changelog
+
+All notable changes to this project are documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [0.1.0] - 2026-06-02
+
+Initial release. A PHP extension that evaluates Cedar policies locally with an
+Amazon Verified Permissions (AVP) compatible API. The evaluation engine is a
+snapshot of nxe-cedar (Cedar for the NGINX edge) at v0.3.0, vendored under
+`src/cedar/` and adapted for the PHP extension.
+
+### Added
+
+- `Cedar\PolicyStore` — a container for one or more Cedar policies, with
+  inline parsing, file loading (`loadFile()`), and a stable store id.
+- `Cedar\AuthorizationClient` — an AVP-compatible evaluation client whose
+  `isAuthorized()` argument structure matches
+  `Aws\VerifiedPermissions\VerifiedPermissionsClient::isAuthorized()`,
+  allowing a single interface to switch between AVP and this extension.
+- `isAuthorizedWithToken()` with a JWT claim mapper, including identity- and
+  access-token claim fallback and custom claim support.
+- `context.contextMap` and `entities.entityList` request inputs.
+- Non-scalar `AttributeValue` variants: `ipaddr`, `decimal`, `set`, `record`,
+  `entityIdentifier`, `datetime`, and `duration`.
+- Cedar syntax coverage including `is` / `is in`, `like`, `if then else`, and
+  policy annotations.
+- Exception hierarchy: `Cedar\Exception\PolicyParseException`,
+  `EvaluationException`, and `ResourceNotFoundException`.
+- Thread-safe (ZTS) builds in addition to NTS, declared in the PIE manifest
+  and exercised in CI.
+- README with installation (PIE), usage, AVP drop-in replacement notes, and a
+  build/test matrix; MIT license; PIE manifest (`composer.json`); GitHub
+  Actions CI running `make test` across the PHP 8.4 / 8.5 × NTS / ZTS matrix.
+
+[0.1.0]: https://github.com/kjdev/php-ext-cedar/releases/tag/v0.1.0
diff --git a/php_cedar.h b/php_cedar.h
index 2e2514a..b7bf04b 100644
--- a/php_cedar.h
+++ b/php_cedar.h
@@ -7,7 +7,7 @@
 
 #include "php.h"
 
-#define PHP_CEDAR_VERSION "0.1.0-dev"
+#define PHP_CEDAR_VERSION "0.1.0"
 #define PHP_CEDAR_NS "Cedar"
 
 extern zend_module_entry cedar_module_entry;