Apple Seems to Also Believe in Multipath TCP ⇥ perso.uclouvain.be
Olivier Bonaventure [sic]:
You won’t see Multipath TCP for regular TCP connections from applications like Safari, but if you use SIRI, you might see that the connection with one of the apple servers runs uses Multipath TCP.
In a nut, this means that using some Apple services — Siri, for example — will use whatever network connection is fastest, whether that’s WiFi, cellular, or whatever. iOS will automatically and seamlessly switch between these as necessary.