"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
AirPods and AirPower: Everything We Know
Rumored Product Introductions Today: Mac Minis, iMac, AirPort, Time Capsules? [Updated]
The claimed introductions so far include three models of the Mac mini with one lacking an optical disc drive, a 21.5" iMac possibly carrying a widescreen 16:9 display, and updated AirPort Extreme and Time Capsule models.
MC207LL/A - K84 BEST BTR- USA
MC238LL/A - MAC MINI 2.26/2x1GB/160/SD/AP/BT-USA
MC239LL/A- MAC MINI 2.53/2x2GB/320GB/SD/AP/BT-USA
MC340LL/A - AIRPORT EXTREME (SIM DUALBAND) - USA
MC343LL/A - TIME CAPSULE 1TB (SIM DUALBAND) -USA
MC344LL/A - TIME CAPSULE 2TB (SIM DUALBAND) - USA
MC408LL/A - MAC MINI 2.53/2x2GB/1TB/NO ODD/AP-BT-USA
MC413LL/A - IMAC 21.5"/3.06/2x2GB/1TB/4670-256MB-USA
MC434LL/A - APPLE VESA MOUNT ADAPTER
MC461LL/A - MACBOOK 60W MAGSAFE POWER ADAPTER - USA
Update: MacRumors has received unconfirmed word that the "MC207LL/A" product is a MacBook running at 2.26 GHz with a 250 GB hard drive and 2 GB of 1066 MHz DDR3 RAM.