diff --git a/version.py b/version.py
index de7eb74..6486924 100644
--- a/version.py
+++ b/version.py
@@ -26,4 +26,4 @@
 # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 # SOFTWARE,  EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-__version__ = "4.2.0"
+__version__ = "4.2.1a1"