"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Mac Pro Build-to-Order Ship Dates Slip as Future Remains Uncertain
Quad-core Mac Pro shipping estimate bumped to 1-3 weeks by upgrading RAM
Increases in shipping estimates in Apple's online store can sometimes be indicative of an upcoming product refresh as the company draws down supplies ahead of launching the updated models. The Mac Pro is most certainly due for an update, and there are several indications that components may be coming together for a significant upgrade to the line.
Most importantly, Intel's Sandy Bridge E Xeon processors are due for launch during the first quarter of this year after having been delayed from a late 2011 debut. Rumors have suggested, however, that continued issues with the chipset portion of the "Romley" platform utilizing the Sandy Bridge E Xeon processors may see a release being held back until the beginning of March, still several months from now.
On the graphics front, evidence of support for AMD's "Tahiti" line of graphics cards has been showing up in developer builds of OS X 10.7.3, and just a week and half ago AMD officially unveiled the first Tahiti graphics card for a January launch.
But while the pieces seem to be coming together at the right time for a substantial Mac Pro upgrade, a bigger question is whether the line will even continue to survive long enough to see another update. A late October report claimed that Apple is "questioning" the future of the Mac Pro given declining sales as customers have continued a trend of shifting toward portable computers, and we've heard similar rumblings that even pinpointed a discontinuation date in January.
Consequently, it is difficult to speculate on whether increased shipping estimates for custom configurations might be due to Apple tightening supplies ahead of a refresh or if the company could be drawing down production entirely ahead of a discontinuation of the line.