I've been getting regular requests for an update on when the Windows Installer 4.5 Beta will start. The answer has unfortunately become 'any day now'. While I'm not happy with this is answer, it is the most accurate one for now.
If you're wondering why the wait, we've found an unexpected diversity of custom action implementations on top of the Windows Installer that have had issues on the Beta. Rather create noise for packages that will run on top of the beta, we're taking more time to fix the issues. Each issue we fix means test needs to run their sanity test pass one more time.
For those of you awaiting the beta, we thank you for your patience. We are eager to get our work into your hands and hear your feedback.