Sparkle 
is an easy-to-use software update framework for Cocoa developers.
This fork
- Up to date with 10.9 SDK and Xcode 5.1.
- Merged bugfixes, security fixes and some features from multiple Sparkle forks.
- Merged official Sparkle branch with truly automatic background updates (no UI at all) when user agreed to "Automatically download and install updates in the future."
- Ability to mark updates as critical.
- Progress and status notifications for the host app.
- Name of finish_installation.app can be configured to match your app's name.
Features
- True self-updating—no work required from the user.
- Displays release notes to the user via WebKit.
- Displays a detailed progress window to the user.
- Supports authentication for installing in secure locations.
- Really, really easy to install.
- Uses appcasts for release information.
- The user can choose to automatically download and install all updates.
- Seamless integration—there's no mention of Sparkle; your icons and app name are used.
- Supports DSA signatures for ultra-secure updates.
- Sparkle requires no code in your app, so it's trivial to upgrade or remove the module.
- Optionally sends user demographic information to the server when checking for updates.
- Sparkle doesn't bug the user until second launch for better first impressions.
- Sparkle can install .pkg files for more complicated products.
- Supports bundles, preference panes, plugins, and other non-.app software.
- Supports branches due to minimum OS version requirements.
- Deep delegate support to make Sparkle work exactly as you need.