"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Apple Seeds Second iOS 8.3 Beta to Developers
The beta is available through the iOS Developer Center. It includes Xcode 6.3 and a new version of Apple's programming language, Swift. Apple has also released a new Apple TV beta for third-generation Apple TVs.
While iOS 8.2 appears to bring only minor bug fixes to the operating system along with the WatchKit SDK and support for the Apple Watch, the first beta of iOS 8.3 introduced several new features including support for wireless CarPlay connectivity, a new emoji picker, support for Google 2-step verification, and Apple Pay support for the China UnionPay network. It also removes the "beta" label from iCloud Photo Library.
iOS 8.3 will be released following iOS 8.2, which is expected in March, so it may be a few months yet before we see a public iOS 8.3 launch.
What's new in iOS 8.3 beta 2:
Release notes - According to iOS 8.3 release notes, the new beta is not compatible with LTE Voice on Verizon. Apple asks that customers using Verizon set LTE to data only. There's also been a fix to the dialog that appears when an iPhone is connected to a CarPlay-compatible car.
Emoji - iOS 8.3 beta 2 introduces all new diversified emoji and skin tone modifiers. There are also new country flags and updated emoji for the iPhone, iMac, and Apple Watch.
Siri - Siri has gained support for several new languages, including Danish, Dutch, English (India), English (New Zealand), Portuguese (Brazil), Russian, Swedish, Thai, and Turkish.
Crash reporting - The new Xcode 6.3 beta 2 update includes a crash log reports service that collects and aggregates crash log data into crash reports that will be available in Xcode.