The Roku 2 and Roku LT — one of our recommended holiday gifts — are receiving an update to version 4.2 that adds support for an official iPhone app and MKV playback. Although MKV support is currently limited to the Roku 2 XS's USB port, the iPhone app should work on all four current Roku boxes and will be in the iTunes App Store soon, followed by an Android version. We're not sure exactly what the app will do, but there are several third party apps that work as a remote, so we'd expect at least that basic functionality. Version 4.2 also improves gaming support, Wi-Fi performance, and Bluetooth remote battery life, and fixes an audio glitch on some stereo receivers. The update will come automatically in the next 48 hours, or you can force it early in the settings.