diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index bd80f06b..5c753b44 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "6.3.0-beta.10"
+  ".": "6.3.0"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ebf7e135..f0730641 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Changelog
 
-## [6.3.0-beta.10](https://github.com/adcontextprotocol/adcp-client-python/compare/v6.3.0-beta.9...v6.3.0-beta.10) (2026-06-12)
+## [6.3.0](https://github.com/adcontextprotocol/adcp-client-python/compare/v6.3.0-beta.9...v6.3.0) (2026-06-18)
 
 
 ### Features
@@ -11,6 +11,7 @@
 
 ### Bug Fixes
 
+* **protocol:** pin AdCP 3.1 stable
 * **schemas:** stamp primary latest fallback caches with the requested prerelease version
 
 ## [6.3.0-beta.9](https://github.com/adcontextprotocol/adcp-client-python/compare/v6.3.0-beta.8...v6.3.0-beta.9) (2026-06-07)
diff --git a/pyproject.toml b/pyproject.toml
index 7f37e9c0..8ef40a50 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "adcp"
-version = "6.3.0b10"
+version = "6.3.0"
 description = "Official Python client for the Ad Context Protocol (AdCP)"
 authors = [
     {name = "AdCP Community", email = "maintainers@adcontextprotocol.org"}