diff --git a/platformio/__init__.py b/platformio/__init__.py
index 1a98a778..94595d2b 100644
--- a/platformio/__init__.py
+++ b/platformio/__init__.py
@@ -14,7 +14,7 @@
 
 import sys
 
-VERSION = (3, 5, 2)
+VERSION = (3, 5, "3a1")
 __version__ = ".".join([str(s) for s in VERSION])
 
 __title__ = "platformio"