Updated models with AMD graphics options expected in early 2017.
iOS 9 and OS X El Capitan Public Betas Coming Soon
When Apple introduced iOS 9 and OS X 10.11 El Capitan at its Worldwide Developers Conference, the company promised that a public beta would be available beginning in July, so customers who are enrolled in Apple's public beta testing programs may not have much longer to wait to get access to the new software.
It is not clear exactly when the public beta will be seeded to customers, but the wording in the support document suggests beta testers will be receiving access to the same third betas of iOS 9 and OS X 10.11 that were seeded to developers this morning.
Public beta tests for major software releases are a relatively new feature from Apple, introduced for OS X with OS X Yosemite last year and iOS with the release of iOS 8.3 in March of 2015. iOS and Mac users can sign up for Apple's Beta Software Program on the company's dedicated beta testing site.