
Apple today seeded the first beta of an upcoming OS X El Capitan update to developers, two weeks before OS X El Capitan will be released to the public on September 30.
The new beta, build 15B17c, is available through the Software Update mechanism in the Mac App Store and through the Apple Developer Center.

It is not clear what improvements the first update to OS X El Capitan will bring, but it's likely to include bug fixes and performance improvements for issues that have been encountered following the operating system's official release.
Update: OS X 10.11.1 includes support for Unicode 8 and a range of new emoji like taco, burrito, cheese wedge, hot dog, middle finger, and unicorn head. The emoji are also included in iOS 9.1, which is currently in testing as well.
Article Link: Apple Seeds First OS X 10.11.1 El Capitan Beta to Developers