With the launch of the iPhone 5 (or iPhone 6, or, most likely, "new iPhone") getting ever closer, Apple appears to be reducing its orders of the current generation iPhone 4S. The reduction is not large yet, as the launch is still about five months away (probably), and Apple can still sell an awful lot of the iPhone 4S in that time.
According to Shaw Wu of Sterne Agee, though, Apple's orders of the iPhone 4S have dropped to around 27 million for the current quarter. Wu speculates that the reduction in orders is not being driven by a reduction in demand. Rather Apple is preparing itself for the sharp dip in demand that is likely to occur in the month or so prior to the launch of the next iPhone in October (or maybe September).
Wu also said that he expects Apple's reduction in iPhone orders to cause Apple to miss Wall Street estimates unless analysts revise their expectations. Apple missed expectations in the September quarter of last year due to a similar reduction in iPhone shipments prior to the launch of the iPhone 4S. On the flip side, Wu also said that he expects shipments of the new iPad to meet or exceed Wall Street estimates, which may alleviate some of the problems caused if iPhone shipments do not meet expectations.
While Apple tends not to comment on things like how many iPhones they're ordering or selling (at least until their earnings call), and it's difficult to know whether Wu's estimation is correct, a move like this does make sense. Apple sold 35.1 million iPhones last quarter, but that was still only the second quarter since the iPhone 4S launched. It stands to reason that the natural decline in iPhone sales, coupled with the anticipation of the next iPhone's launch, would prompt Apple to reduce the number of phones it's ordering over the next two quarters.