Almost exactly a year ago, the Bluetooth Special Interest Group (SIG) announced Bluetooth 4.1, an update that improved speed for bulk data transfers, reduced the likelihood of LTE interference, and made it easier for various "smart" devices to talk directly to one another without using a hub like a phone or computer as an intermediary. The final update to the spec laid the groundwork for the introduction of IPv6 to the Bluetooth specification—the newly announced Bluetooth 4.2 completes that work, and devices that support it will be able to access the Internet directly over IPv6 and 6LoWPAN.
Other improvements to the specification concern themselves with privacy and speed. With Bluetooth 4.2, Bluetooth beacons attempting to connect to and track your device can't do so unless you've given them permission. Transfer speeds between two Bluetooth devices have also improved by "up to 2.5 times" thanks to increased capacity for Bluetooth Smart data packets, which can now contain about ten times as much data as before.
It was possible for existing Bluetooth 4.0 adapters to support Bluetooth 4.1 with a software update, and we've contacted the Bluetooth SIG to confirm that this is also the case for Bluetooth 4.2. Version 4.0 is still by far the most common version of the spec in shipping consumer devices, though mobile platforms like Android Lollipop have begun to add native support for version 4.1.
If you're interested in learning more, the Bluetooth SIG has published extensive technical information on Bluetooth 4.2 and earlier versions of the spec on this page.
Update: Apparently some but not all Bluetooth 4.2 features will be available as an update for older Bluetooth adapters. "Privacy features may be available via firmware update, but it does ultimately depend on the manufacturer implementation," a representative for the Bluetooth SIG told Ars. "The increased speed and packet size features will require a hardware update." The representative is also checking to see whether the FCC will need to recertify older Bluetooth 4.x adapters before they can support Bluetooth 4.2 features. In any case, it doesn't appear as though older hardware will be able to take full advantage of the newer spec.
Update 2: The Bluetooth SIG says there is "definitely no need for FCC recertification" if an OEM chooses to update an existing adapter to support Bluetooth 4.2 features.
