diff --git a/CHANGELOG.md b/CHANGELOG.md
index 217dbacb8..69d3b4c8e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,8 @@
 # Change Log
 All notable changes to this project will be documented in this file. This project adheres to [Semantic Versioning](http://semver.org)
 
+## 4.0.1-dev
+
 ## 4.0.0 - 2025-05-07
 
 ### Added
diff --git a/config/constants.yml b/config/constants.yml
index 3d09f12cb..f89e12f36 100644
--- a/config/constants.yml
+++ b/config/constants.yml
@@ -7,7 +7,7 @@
 ---
 
 # App
-TERMINUS_VERSION: '4.0.0'
+TERMINUS_VERSION: '4.0.1-dev'
 
 # Connectivity
 TERMINUS_HOST:        'terminus.pantheon.io'