The Federal Communications Commission has posted test results for what looks to be a possible refresh of the AirPort Extreme. It's tough to learn much about what's changed in the wireless hardware from the reports because Apple filed a request to keep all proprietary details confidential. However, the results show that tests were done in both 2.4 Ghz and 5Ghz bands, and the speculation is that there could be support for the new three-stream standard for 450Mbps.
The FCC package includes a mock-up of where Apple would place its compliance label on the 3-by-3 unit, which is identified as the AirPort Extreme Base Station Model A1408. Rumors of updates to the AirPort and also to TimeCapsule models have been swirling since Apple's Worldwide Developers Conference, but no releases have been announced. The last big refreshes for either came in 2009, with the first dual-band AirPort Extreme.
This FCC release would appear to confirm that release of at least the Airport Extreme update is imminent. In the past, products have been officially released within hours of this kind of FCC posting.
9to5 Mac also claims to have received part numbers for not only the new AirPort Extreme, but also for new Time Capsules in 2 TB and 3 TB models. Rumor also has it that we should expect a price drop and improved signal strength in a new AirPort Extreme. It makes sense for Apple to get some of its most stale peripherals looking all shiny and new in advance of the release of the new MacBooks and more. Many more Apple product announcements along such lines are expected by the end of the summer.