diff --git a/.github/release-notes/v0.4.0.md b/.github/release-notes/v0.4.0.md
new file mode 100644
index 0000000..0ee3d96
--- /dev/null
+++ b/.github/release-notes/v0.4.0.md
@@ -0,0 +1,25 @@
+OffPDF v0.4.0 completes the direct-editing foundation while keeping unsupported PDF structures fail-closed.
+
+Highlights:
+
+- Source-content inspection uses one bounded input snapshot with deterministic locators.
+- Oversized, malformed, compressed, or ambiguous content is rejected explicitly.
+- Font encodings and unsafe PDF text-state operators are checked before a source edit can be considered.
+- Desktop job identifiers are validated before filesystem use.
+- Operating-system file intake keeps the original file order.
+- CI requires the same PDF engines exercised by production paths.
+
+This release does not claim Word-like editing for arbitrary PDFs. Existing source text and image replacement remains limited to separately proven structures; overlays continue to be treated as new content.
+
+Known issue:
+
+- Some real-device HEIC/HEIF files may still crash on Windows; investigation continues in issue #14.
+
+Thanks to @Aaqibhafeezkhan for contributing to this release.
+
+Packages:
+
+- Signed and notarized DMG for Apple Silicon Macs
+- Windows x64 NSIS installer — unsigned while Authenticode signing is pending. Verify the accompanying SHA-256 file before use.
+
+See [CHANGELOG.md](https://github.com/McanKul/offpdf/blob/v0.4.0/CHANGELOG.md) for full details.
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7bf5add..bff5edd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,32 @@ All notable project changes should be documented here.
 
 ## Unreleased
 
+## 0.4.0 - 2026-10-05
+
+### Added
+
+- Completed the v0.4 direct-editing foundation with a documented compatibility matrix and an explicit boundary between safe overlays and narrowly proven source-content edits.
+- Added deterministic, read-only source locators for supported whole-string text and uniquely referenced image structures without exposing a general save capability.
+
+### Fixed
+
+- Source-content inspection now reads from one bounded snapshot and fails closed on oversized, malformed, compressed, or ambiguous PDF structures.
+- Cross-reference tables, indirect objects, decoded content streams, font encodings, and unsafe text-state operators are bounded or rejected with explicit reasons.
+- Desktop job identifiers are validated before they can reach temporary filesystem paths.
+- Files opened through the operating system retain their original intake order.
+
+### CI
+
+- Rust CI now installs and requires the PDF engines used by production paths instead of silently skipping their tests.
+
+### Contributors
+
+- Thank you to @Aaqibhafeezkhan for contributing to this release.
+
+### Known issues
+
+- Some real-device HEIC/HEIF files may still crash on Windows; investigation continues in issue #14.
+
 ## 0.3.2 - 2026-09-11
 
 ### Added
diff --git a/package-lock.json b/package-lock.json
index 26e4eb3..e0d31b0 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "offpdf",
-  "version": "0.3.2",
+  "version": "0.4.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "offpdf",
-      "version": "0.3.2",
+      "version": "0.4.0",
       "license": "MIT",
       "dependencies": {
         "@tauri-apps/api": "^2.1.1",
diff --git a/package.json b/package.json
index 0049c24..316e619 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "offpdf",
   "private": true,
-  "version": "0.3.2",
+  "version": "0.4.0",
   "type": "module",
   "description": "Free, open-source, offline-first desktop PDF utility.",
   "license": "MIT",
diff --git a/src-tauri/Cargo.lock b/src-tauri/Cargo.lock
index 2d7686c..d357649 100644
--- a/src-tauri/Cargo.lock
+++ b/src-tauri/Cargo.lock
@@ -2846,7 +2846,7 @@ dependencies = [
 
 [[package]]
 name = "offpdf"
-version = "0.3.2"
+version = "0.4.0"
 dependencies = [
  "flate2",
  "fs2",
diff --git a/src-tauri/Cargo.toml b/src-tauri/Cargo.toml
index d8291ef..72fe163 100644
--- a/src-tauri/Cargo.toml
+++ b/src-tauri/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "offpdf"
-version = "0.3.2"
+version = "0.4.0"
 description = "Free, open-source, offline-first desktop PDF utility."
 authors = ["OffPDF contributors"]
 edition = "2021"
diff --git a/src-tauri/tauri.conf.json b/src-tauri/tauri.conf.json
index 3affb51..8b4395d 100644
--- a/src-tauri/tauri.conf.json
+++ b/src-tauri/tauri.conf.json
@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "OffPDF",
-  "version": "0.3.2",
+  "version": "0.4.0",
   "identifier": "app.offpdf.desktop",
   "build": {
     "frontendDist": "../dist",