diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3cce4489..06f836ab 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,7 +5,20 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
-## [Unreleased]
+## [0.4.0]
+
+### Added
+
+* DAKOTA plugin via the `PluginDakota` class
+* ABCE plugin via the `PluginABCE` class
+* Ability to define a generic plugin via the `PluginGeneric` class
+* The `Database` class now has a `remove` method that allows a single result to
+  be removed
+
+### Changes
+
+* The OpenMC plugin unit test no longer requires the `OPENMC_CROSS_SECTIONS`
+  environment variable to be set
 
 ## [0.3.0]
 
diff --git a/doc/source/_static/switcher.json b/doc/source/_static/switcher.json
index 483d2ca5..a9464b1e 100644
--- a/doc/source/_static/switcher.json
+++ b/doc/source/_static/switcher.json
@@ -4,6 +4,11 @@
         "version": "latest",
         "url": "https://watts.readthedocs.io/en/latest/"
     },
+    {
+        "name": "0.4.0",
+        "version": "v0.4.0",
+        "url": "https://watts.readthedocs.io/en/v0.4.0/"
+    },
     {
         "name": "0.3.0",
         "version": "v0.3.0",
diff --git a/pyproject.toml b/pyproject.toml
index 3f6dba91..48e850ad 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "flit_core.buildapi"
 
 [project]
 name = "watts"
-version = "0.3.1-dev"
+version = "0.4.0"
 authors = [
     { name = "UChicago Argonne, LLC", email = "watts@anl.gov" },
 ]
diff --git a/src/watts/__init__.py b/src/watts/__init__.py
index 499606aa..3074636f 100644
--- a/src/watts/__init__.py
+++ b/src/watts/__init__.py
@@ -19,4 +19,4 @@
 # This allows a user to write watts.Quantity
 from astropy.units import Quantity
 
-__version__ = '0.3.1-dev'
+__version__ = '0.4.0'