diff --git a/sipclient/__init__.py b/sipclient/__init__.py
index a373a37..b4523e4 100644
--- a/sipclient/__init__.py
+++ b/sipclient/__init__.py
@@ -1,2 +1,2 @@
 
-__version__ = '3.5.6'
+__version__ = '4.0.0'