Firefox 15 is released on August 28th. Among many new features implemented in this release is background updates. This feature allows Firefox to download the update in the background, apply it alongside with the existing installation, and keep the updated version around so that it can quickly switch to it the next time that the browser starts up. This effectively eliminates the update progress dialog that appears when you start Firefox after it has downloaded an update:
I previously wrote about this project. You can see that post for more technical details. This feature landed a while ago on the Nightly channel, and we soon discovered a few issues which we addressed in time for this to get uplifted and enabled on the Aurora channel. Luckily no new issues were discovered with this feature as it rode the train to get on the Beta channel, and will get in the hands of all of Firefox users on Windows, Mac and Linux as part of the Firefox 15 release.
This was one of the scariest projects that I've ever worked on, since messing something up in the updater component could have catastrophic consequences in case it prevents users from being able to update to newer Firefox revisions. I'm happy that the results of this project will soon get in the hands of millions of Firefox users, and I would like to thank Robert Strong, Brian Bondy, and the wonderful members of our Release Engineering (in particular, Ben Hearsum and Chris AtLee) and QA teams (in particular, Vlad Ghetiu) who helped me a lot along the way. You guys rock, for being extremely helpful, and for making this large project possible!