Image credit: Apple. 

Qualcomm (NASDAQ:QCOM) is currently the only company that supplies stand-alone cellular modems in new Apple (NASDAQ:AAPL) iPhones. Apple is also probably the only smartphone maker that uses stand-alone modems in large quantities.

This means that a reasonable way to get a read on how Apple might be doing would be to listen for any clues around the demand and/or mix of what Qualcomm refers to as "slim modems" (i.e. modems not integrated with an applications processor).

Unfortunately for Apple stock, the clues from Qualcomm's call weren't positive.

Here's what Qualcomm had to say
On Qualcomm's call, analyst C.J. Muse noted that Qualcomm's implied revenue guidance per MSM (modems and applications processors that integrate modems) is headed upwards in the coming quarter.

Qualcomm CFO George Davis explained this outlook as follows (emphasis mine):

I think the dynamics that are driving the significant pickup that we are seeing in Q3 remain in place for Q4; very good mix, strong demand for our premium tier, again, a shift from low tier into the mid and high tier, and then some softness certainly comparatively year over year on thin modem volumes, which tend to depress revenues per MSM.

This commentary seems to suggest that thin modem shipments to Apple should be down in the current quarter (June quarter) and down again in the following quarter. This may dash some hopes around Apple potentially seeing enough stabilization following its widely reported "inventory adjustment" to get shipments to around flattish year-over-year.

This seems to corroborate other reports
Prior to Qualcomm's earnings call, there were other reports suggesting that iPhone weakness would continue into the coming quarters.

For example, Nikkei Asian Review -- which was one of the first, if not the first, to report on the initial round of supply chain cuts earlier this year -- published an article claiming that Apple's supply chain cuts would extend into the April-June quarter.

KGI Securities' Ming-Chi Kuo, who was one of the first analysts to publicly suggest that the iPhone 6s-series would decline relative to the iPhone 6-series, also recently published a fairly dim view of iPhone shipments for 2016. According to Kuo, iPhone sales in 2016 could hit only between 190 million and 210 million units.

Expect disappointment on earnings day
I don't think that it's reasonable to expect Apple's iPhone shipments (which make up the majority of its revenue and profits) to surprise on earnings day, scheduled for April 26. There's good reason to believe that iPhone shipments will continue to see year-over-year declines in the coming two quarters.

Beyond those two quarters is hard to call. On one hand, some investors and analysts have been expecting an iPhone 6-esque "super cycle" with the iPhone 7. Although I expect significant generation-over-generation innovations, particularly with respect to the internal components, the "big" redesign that some may have been hoping for might not arrive until the 2017 iPhone.

Though far from a foregone conclusion, there is risk that Apple may once again see year-over-year iPhone unit declines in the coming product cycle, particularly if the really noticeable improvements are being saved up for a future iPhone.