diff --git a/setup.py b/setup.py
index 0073ff0f..f9751244 100644
--- a/setup.py
+++ b/setup.py
@@ -2,7 +2,7 @@
 from setuptools import setup
 
 
-version = "4.0.0"
+version = "4.0.1.dev0"
 
 install_requires = [
     "setuptools",