diff --git a/synop2bufr/__init__.py b/synop2bufr/__init__.py
index 4b2c0e8..5ab9ed8 100644
--- a/synop2bufr/__init__.py
+++ b/synop2bufr/__init__.py
@@ -32,7 +32,7 @@
 from csv2bufr import BUFRMessage
 from pymetdecoder import synop
 
-__version__ = '0.5.0'
+__version__ = '0.5.dev1'
 
 LOGGER = logging.getLogger(__name__)