diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8a0efa9..867e1ef 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,22 @@
 # Changelog
 
+## v1.0.0 - 2026-09-19
+
+### Added
+
+- Add `Lettermint::email` for the Sending API.
+- Add `Lettermint::api` for the Team API.
+- Add generated Sending and Team API types and endpoint clients.
+- Add scheduled delivery, typed message tags, a custom transport interface, and webhook verification.
+- Add a 0.3-to-1.0 migration guide.
+
+### Changed
+
+- Replace the 0.3 public client interface with the new SDK interface.
+- Generate API source from the central Lettermint OpenAPI specifications without copying the specifications into this repository.
+
+Applications that use `lettermint = "0.3"` continue to resolve to the compatible 0.3 release line.
+
 ## Unreleased
 
 - Initial Rust SDK with async sending client, team API client, generated serde DTOs, webhook verification, tests, and release workflows.