diff --git a/buildtools/version.py b/buildtools/version.py
index 579284c4..0218542c 100644
--- a/buildtools/version.py
+++ b/buildtools/version.py
@@ -24,9 +24,9 @@ PROJECT_NAME     = 'wxPython'
 # version numbers.
 VER_MAJOR        = 4
 VER_MINOR        = 2
-VER_RELEASE      = 0
+VER_RELEASE      = 1
 
-VER_FLAGS        = ""     # wxPython release flags
+VER_FLAGS        = "a1"     # wxPython release flags
 
 # The VER_FLAGS value is appended to the version number constructed from the
 # first 3 components and should be set according to the following patterns.