Google frees Update Engine for Mac OS X
Google has released Update Engine, an open source framework for Mac OS X, which allows developers to incorporate automatic update functionality within their own applications. The Update Engine has been released under an Apache licence, making it freely available for open source and proprietary software.
Google Update Engine will be up against Sparkle, also open source, by Andy Matuschak. Sparkle is already widely used in Mac OS X applications. Matuschak seems quite impressed, saying "Update Engine looks much better-designed than Sparkle though a little clunkier in a few minor ways".
Google Update Engine is able to update applications but also extends to being able to update screensavers, preference panes and kernel extensions. It can be called from the commandline or embedded directly into an application with the Objective C API. Update Engine was originally developed to distribute Google's Mac OS X applications.