"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
AirPods and AirPower: Everything We Know
Video Compares iPhone 6 Plus 802.11ac Wi-Fi Speeds to 802.11n iPhone 5s Speeds
iClarified has created a new video that compares the Wi-Fi speeds of the iPhone 6 Plus, which supports 802.11ac, to the iPhone 5s, which supports 802.11n, when connected to an AirPort Extreme. The site also created a custom app for the test.
Both devices were freshly restored to iOS 8.0 and connected to the 2013 Apple AirPort Extreme. The router was placed 1.5 metres away from the smartphones and each iPhone was connected to the AirPort Extreme using a 5GHz-only network. No other devices were connected to the wireless network at the time of the test and the downloads were performed at separate times. We cut them together for comparison.As expected, the iPhone 6 Plus sees much faster connection speeds that reach 278.5 Mbps, while the iPhone 5s tops out at approximately 101.1 Mbps. While speeds are improved in this test, the actual speeds that users see in the real world will vary based on connection strength and other factors, as an actual ISP connection is generally the limiting factor for speeds when connecting to the Internet. When an 802.11ac Wi-Fi network is available, however, iPhone 6 and 6 Plus users should see significant speed improvements.
Along with 802.11ac Wi-Fi, the iPhone 6 and 6 Plus offer several other connectivity improvements, including faster LTE with support for LTE Advanced and voice over LTE, which enables higher-quality phone calls. The iPhone 6 also supports calls over Wi-Fi, for access to high-quality voice connections even in areas where cellular connection is poor.