Apple's yearly developer conference should see iOS 8, OS X 10.10, and likely some hardware.
New Apple TV Hardware References Found in iOS 7 Software Builds
There is a reference to the AppleTV4,1 listed in the iOS 7 Apple TV framework that handles AirPlay. AppleTV4,1 does not correlate to an existing Apple TV device, thus pointing to new hardware.
The current Apple TV (which was tweaked in 2013) is listed internally as AppleTV3,2, while AppleTV3,1 refers to the 1080p device released in 2012. AppleTV2,1 references the first ios-based Apple TV released in 2010.
According to 9to5Mac, references for AppleTV4,1 first appeared in the original version of iOS 7 released in September, but were not discovered until recently. AppleTV4,1 appears to be a reference to an entirely new device that is more than just an iterative update to Apple's existing set-top box.
An updated Apple TV has been expected for quite some time, as Apple's last refresh of the device was a minor tweak last year that saw the device upgraded to a smaller A5 chip. The device has otherwise retained the same look and functionality since the third-generation Apple TV was released in March of 2012.
Rumors have suggested that the revamped box might include game support, an Apple TV-based App Store, and support for Bluetooth controllers. Apple is also said to be testing a set-top box that combines the Apple TV with wireless router functionality and the company may also be testing a version of the device with a TV-tuner component allowing users to pull in content from their existing cable boxes, overlaying channels with an Apple interface.
Recently, Apple revised its online storefront to give the Apple TV greater prominence, suggesting it has moved past the "hobby" status that Apple executives have long assigned it. Over the course of the last several months, Apple has worked hard to boost the content it offers on the Apple TV, adding a number of channels including ABC, Bloomberg, Crackle, KORTV, Redbull TV and The Beatles channel, which was just added today.