The venerable iPhone 5s. Image credit: Apple. 

Apple (NASDAQ:AAPL) faces the prospect of its first-ever year-over-year decline in iPhone sales after nearly a decade of robust growth. The decline is generally believed to be some combination of macroeconomic headwinds and a lukewarm reception to the company's newest iPhones, the iPhone 6s and 6s Plus.

In a bid to shore up demand for the company's most important product category, Apple is planning to launch a refreshed 4-inch iPhone, which 9to5Mac reports will be known as the iPhone SE. Let's take a look at what Apple reportedly has in store with this soon-to-be-launched device.

Significant internal upgrades
The iPhone SE is widely expected to pack Apple's latest A9 processor, the same one that's found inside of the iPhone 6s and 6s Plus. Additionally, per 9to5Mac's Mark Gurman, the device will come with an updated wireless subsystem with support for fast 802.11ac Wi-Fi (the 5s currently supports just 802.11n), Voice over LTE, and Bluetooth 4.2.

In addition to the faster connectivity, Gurman says that the device will include an NFC chip, a component required to support Apple's contactless payment service, Apple Pay.

Camera upgrades, too
Both Mark Gurman as well as KGI Securities analyst Ming-Chi Kuo claim that Apple will include an updated camera subsystem compared to the iPhone 5s. However, there seems to be a disagreement between these two individuals -- both of whom are quite well connected and reliable -- so it's worth taking a look at what each has to say.

According to Gurman, the iPhone SE will pack a similar camera subsystem to what the 2014 iPhone 6 came with -- an updated 8-megapixel rear sensor and a 1.2-megapixel front facing camera.

Kuo, on the other hand, does not appear to give information about the front facing camera, but does say that the iPhone SE's rear shooter will pack a 12-megapixel sensor, likely the same one found in the iPhone 6s/6s Plus.

No 3D Touch
Perhaps the signature feature of the iPhone 6s/6s Plus flagship phones launched back in Sept. 2015 is 3D Touch. The feature, though quite interesting and challenging technically, seems not to have been quite the selling point that Apple had hoped.

Indeed, in a poll run by Phone Arena, only 12.51% of respondents (presumably all iPhone 6s/6s Plus) owners said that they "use it all the time" and 21.74% said that they use it "every now and then." 33.98% said that they use it simply to "show it off to friends and family" while a full 31.77% chose the option, "What's 3D Touch?"

Though a poll on a mobile-focused website isn't going to be perfect (how do we know that all respondents even own an iPhone 6s/6s Plus?), I think that the results seem to suggest that it's not really a "game changing" feature -- at least not yet.

With that in mind, the iPhone SE is expected to come sans 3D Touch. On one hand, it would seem that this is a sensible move given the seemingly lukewarm reception to the feature (and the added cost), but on the other, one would think that Apple would like to push 3D Touch adoption as hard as possible.

At any rate, this is a feature that I'm sure will come with the next update of the 4-inch iPhone -- whenever that ultimately comes.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.