diff --git a/.github/workflows/deploy-website.yml b/.github/workflows/deploy-website.yml
index ca368bf8..8956ba18 100644
--- a/.github/workflows/deploy-website.yml
+++ b/.github/workflows/deploy-website.yml
@@ -28,7 +28,7 @@ env:
   ALGOLIA_INDEX_NAME: akkurate
   ALGOLIA_KEY: ${{ secrets.ALGOLIA_KEY }}
   CONFIG_JSON_PRODUCT: AKKURATE
-  CONFIG_JSON_VERSION: 0.3.0
+  CONFIG_JSON_VERSION: 0.4.0
 
 jobs:
   build-documentation:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2b6ffdbc..8ff84fe2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,8 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
 
+## [0.4.0] - 2023-10-30
+
 ### ⚠️ Breaking changes
 
 - The `Configuration` class is now instantiated through a builder DSL ([#13](https://github.com/nesk/akkurate/issues/13))
@@ -78,7 +80,8 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 First release
 
-[Unreleased]: https://github.com/nesk/akkurate/compare/0.3.0...HEAD
+[Unreleased]: https://github.com/nesk/akkurate/compare/0.4.0...HEAD
+[0.4.0]: https://github.com/nesk/akkurate/compare/0.3.0...0.4.0
 [0.3.0]: https://github.com/nesk/akkurate/compare/0.2.0...0.3.0
 [0.2.0]: https://github.com/nesk/akkurate/compare/0.1.1...0.2.0
 [0.1.1]: https://github.com/nesk/akkurate/compare/0.1.0...0.1.1
diff --git a/documentation/topics/migration-guide.md b/documentation/topics/migration-guide.md
index 7b996c46..b3c34fab 100644
--- a/documentation/topics/migration-guide.md
+++ b/documentation/topics/migration-guide.md
@@ -3,14 +3,14 @@
 Some breaking changes might happen sometimes, especially until %product% reaches its first stable version. Here you can
 find how to migrate to a new version containing breaking changes.
 
-## #unreleased#
+## Version 0.4.0
 
 The `Configuration`
 declaration [is no longer a data class.](https://kotlinlang.org/docs/jvm-api-guidelines-backward-compatibility.html#don-t-use-data-classes-in-an-api)
 To create a new configuration, use the following builder DSL:
 
 <tabs>
-<tab title="After v#unreleased#">
+<tab title="After v0.4.0">
 
 ```kotlin
 Configuration {
@@ -20,7 +20,7 @@ Configuration {
 ```
 
 </tab>
-<tab title="Before v#unreleased#">
+<tab title="Before v0.4.0">
 
 ```kotlin
 Configuration(
diff --git a/documentation/v.list b/documentation/v.list
index c6c02b8f..fe2f9e38 100644
--- a/documentation/v.list
+++ b/documentation/v.list
@@ -2,7 +2,7 @@
 <!DOCTYPE vars SYSTEM "https://resources.jetbrains.com/writerside/1.0/vars.dtd">
 <vars>
     <var name="product" value="Akkurate"/>
-    <var name="version" value="0.3.0"/>
+    <var name="version" value="0.4.0"/>
     <var name="github_product_url" value="https://github.com/nesk/akkurate"/>
     <var name="roadmap_url" value="https://github.com/users/nesk/projects/1/views/1"/>
     <var name="api_reference_url" value="https://akkurate.dev/api"/>
diff --git a/documentation/writerside.cfg b/documentation/writerside.cfg
index 96e518cf..59e3b4ec 100644
--- a/documentation/writerside.cfg
+++ b/documentation/writerside.cfg
@@ -4,5 +4,5 @@
 <ihp version="2.0">
     <topics dir="topics"/>
     <images dir="images" web-path="images"/>
-    <instance src="akkurate.tree" version="0.3.0"/>
+    <instance src="akkurate.tree" version="0.4.0"/>
 </ihp>
diff --git a/library/build.gradle.kts b/library/build.gradle.kts
index fd29b502..49d81e00 100644
--- a/library/build.gradle.kts
+++ b/library/build.gradle.kts
@@ -8,7 +8,7 @@ plugins {
 }
 
 group = "dev.nesk.akkurate"
-version = "0.3.0"
+version = "0.4.0"
 
 repositories {
     mavenCentral()
diff --git a/plugin/build.gradle.kts b/plugin/build.gradle.kts
index db9752d2..49233a64 100644
--- a/plugin/build.gradle.kts
+++ b/plugin/build.gradle.kts
@@ -17,7 +17,7 @@ buildscript {
 apply(plugin = "com.karumi.kotlin-snapshot")
 
 group = "dev.nesk.akkurate"
-version = "0.3.0"
+version = "0.4.0"
 
 repositories {
     mavenCentral()