diff --git a/.release-please-manifest.json b/.release-please-manifest.json
index 0ee8c01..2537c1f 100644
--- a/.release-please-manifest.json
+++ b/.release-please-manifest.json
@@ -1,3 +1,3 @@
 {
-  ".": "0.3.0"
+  ".": "0.4.0"
 }
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..bc1d2d6
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,22 @@
+# Changelog
+
+## [0.4.0](https://github.com/wadahiro/scim-server/compare/v0.3.0...v0.4.0) (2026-06-13)
+
+### Features
+
+* Publish a multi-arch container image (`linux/amd64`, `linux/arm64`) to GitHub Container Registry (`ghcr.io`) on release ([#49](https://github.com/wadahiro/scim-server/pull/49))
+* Provide release binaries for macOS (Apple Silicon and Intel) and Windows (x64 and ARM64) in addition to Linux x64/ARM64 ([#49](https://github.com/wadahiro/scim-server/pull/49))
+* Build both the binaries and the container image with SQLite **and** PostgreSQL backends enabled ([#49](https://github.com/wadahiro/scim-server/pull/49))
+
+### Bug Fixes
+
+* Report the correct version from `--version` (it had been stuck at a stale `0.2.0`)
+
+### Dependencies
+
+* Bump scim_proto, clap, tokio, regex, serde_json, uuid, async-trait, tracing-subscriber, bcrypt, chrono-tz, and testcontainers; resolve RUSTSEC advisories (rustls-webpki, time, bytes, tokio-tar) and drop the direct `rand` dependency ([d4f878a](https://github.com/wadahiro/scim-server/commit/d4f878ab0f4230a920a2321ecbae625af7f64fca))
+
+### Build System
+
+* Upgrade the Docker runtime image to Alpine 3.24 and modernize the Dockerfile (rust 1.96-alpine builder) ([#59](https://github.com/wadahiro/scim-server/pull/59), [#49](https://github.com/wadahiro/scim-server/pull/49))
+* Automate releases with release-please and harden the CI/release workflows (SHA-pinned actions, least-privilege tokens) ([#51](https://github.com/wadahiro/scim-server/pull/51))
diff --git a/Cargo.lock b/Cargo.lock
index 6670e91..728c0b8 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2637,7 +2637,7 @@ dependencies = [
 
 [[package]]
 name = "scim-server"
-version = "0.3.0"
+version = "0.4.0"
 dependencies = [
  "argon2",
  "async-trait",
diff --git a/Cargo.toml b/Cargo.toml
index 4afc59d..1c89150 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "scim-server"
-version = "0.3.0"
+version = "0.4.0"
 edition = "2021"
 # Application binary, not a library — never publish to crates.io. This also
 # tells release-plz to manage version/changelog/tags without publishing.