diff --git a/lib/iris/__init__.py b/lib/iris/__init__.py
index f88537d2dd..7688026342 100644
--- a/lib/iris/__init__.py
+++ b/lib/iris/__init__.py
@@ -121,7 +121,7 @@ def callback(cube, field, filename):
 
 
 # Iris revision.
-__version__ = '2.0a0'
+__version__ = '2.1.0.dev0'
 
 # Restrict the names imported when using "from iris import *"
 __all__ = ['load', 'load_cube', 'load_cubes', 'load_raw',