diff --git a/CHANGELOG.md b/CHANGELOG.md
index c66f987..8c0e162 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,22 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.4.0](https://github.com/devrandom-labs/cesr/compare/v0.3.0...v0.4.0) - 2026-07-05
+
+### Added
+
+- *(#67)* [**breaking**] infallible Matter::to_qb64 in core (text encoding without stream) (#78)
+- *(#69)* [**breaking**] type-unified, composable signature verification (#72)
+
+### Fixed
+
+- *(#76)* [**breaking**] checked size arithmetic in MatterBuilder variable-size parse (#77)
+
+### Other
+
+- *(#33)* [**breaking**] replace terrors::OneOf with domain error enums (#74)
+- fix deep-fuzz workflow (engine-arg parsing + nightly toolchain) ([#75](https://github.com/devrandom-labs/cesr/pull/75))
+
 ### Changed
 
 - **core (#76):** `ValidationError` gains a new `SizeOverflow` variant, returned
diff --git a/Cargo.lock b/Cargo.lock
index 300b8d6..0861301 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -157,7 +157,7 @@ dependencies = [
 
 [[package]]
 name = "cesr-rs"
-version = "0.3.0"
+version = "0.4.0"
 dependencies = [
  "base64",
  "blake2",
diff --git a/Cargo.toml b/Cargo.toml
index 7056b0c..b547db0 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,7 +4,7 @@
 # consumers still write `use cesr::...` — only the dependency key differs
 # (`cesr-rs = { ... }` or `cesr = { package = "cesr-rs", ... }`).
 name = "cesr-rs"
-version = "0.3.0"
+version = "0.4.0"
 edition = "2024"
 rust-version = "1.95.0"
 license = "MIT OR Apache-2.0"