diff --git a/CHANGELOG.md b/CHANGELOG.md
index d4c7e79..9548c89 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,7 +6,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to
 [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## Unreleased
+## 4.0.1 - 2021-08-26
 
 ### Fixed
 
diff --git a/appveyor.yml b/appveyor.yml
index 5711e17..76cf0fc 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -1,4 +1,4 @@
-version: "4.0.0-{build}"
+version: "4.0.1-{build}"
 branches:
   only:
     - master