Klaas van Schelven has left a comment on the post "Tabbie system" but I thought it was worth a post by itself.
The newest version (1.1.1) can be found on the project's homepage.
This version supports
* An overview page for peace of mind in stressful tab rooms.
* An integrated one-click backup module
* Adjudicator sheets can now be generated with one click as a PDF (no mail merge required)
* The official WUDC rules to calculate its draw. (as before)
More info: Tabbie British Parliamentary Debating Tab Software