"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Apple Increases Maximum App Size from 2GB to 4GB
The size limit of an app package submitted through iTunes Connect has increased from 2 GB to 4 GB, so you can include more media in your submission and provide a more complete, rich user experience upon installation. Please keep in mind that this change does not affect the cellular network delivery size limit of 100 MB.Apple's 2GB size limit has been in place since the App Store first launched, so today's new 4GB limit marks the first-ever size increase. The 2GB size limitation has prevented some games from being available on the App Store, such as Final Fantasy VII. In 2013, Square Enix producer Takashi Tokita said that a version of Final Fantasy VII was "years away" due to the 2GB iOS app size limit.
Over the last several years, as iPhone and iPad displays have improved in quality, developers have needed to increase the size of app assets to create content suitable for Retina screens. The new 4GB limit will give developers more freedom when it comes to content creation and it also paves the way for higher-resolution displays that may require even larger apps.
Though the maximum app size has increased to 4GB, Apple is still enforcing the 100MB over-the-air download limit introduced in 2013.