New 21.5-inch Retina 4K models expected.
Apple Releases Retina MacBook Pro SMC Update to Address Gaming Frame Rates and Fan Issues
About MacBook Pro Retina SMC Update v1.1
This update resolves a rare issue where users may experience slow frame rates when playing graphics-intensive games on the 15-inch MacBook Pro with Retina Display. It also includes bug fixes for Power Nap, wake from sleep and fan control.
Retina MacBook Pro owners will no doubt be testing the update to see whether the fan control bug fixes mentioned in the release notes address the widespread complaints with fan speed spikes under relatively low loads.