diff --git a/PIL/version.py b/PIL/version.py
index 9424f1328..4d21d062b 100644
--- a/PIL/version.py
+++ b/PIL/version.py
@@ -1,2 +1,2 @@
 # Master version for Pillow
-__version__ = '4.2.0'
+__version__ = '4.3.0.dev0'