Software updates are an often forgotten backbone of modern software. The one constant for a piece of deployed software is that it will need to be updated for bugs, security issues and feature additions. Distributing a software update to thousands or even millions of users is a difficult task. There are severe reliability and security challenges. Most applications don't do it right. The recent Conficker worm's update mechanism is a case study of how to create a resilient, cryptographically sound, update mechanism that can defeat legions of Internet infrastructure administrators and malicious attackers attempting to stop or take over the botnet. Google's recently open sourced desktop software update mechanism will be examined as well. These update mechanisms will be compared with the typical, insecure, software update mechanism. These mechanisms usually only provide integrity for their updates, which is not good enough to create a trusted update mechanism. The presentation will focus on how and why to provide authenticity, integrity and even confidentiality in your software update mechanisms.