Last week, I wrote that after a couple of down years, Apple's (NASDAQ:AAPL) iPad was likely to make a comeback starting in 2016. One of the reasons I cited was that current iPad users who bought their devices during 2012 and 2013 -- when iPads seemed to be flying off the shelves -- would start to become interested in upgrading their devices.

Apple's decision not to introduce a new 9.7-inch iPad this fall means that full-size iPad users have an incentive to hold out a little while longer -- unless they want to pay up for the giant iPad Pro. But for users of the first-generation iPad Mini, the upgrade cycle could begin this quarter.

Finally, a worthy iPad Mini upgrade
The iPad Mini was a big hit when it was released in late 2012, driving a huge spike in iPad sales in the first two quarters after it arrived. Subsequent iPad Mini versions weren't nearly as successful, though.

The iPad Mini 2 -- the first with a "retina" display -- was highly anticipated before its launch in late 2013. However, the retina display quality wasn't quite up to par. The third-generation iPad Mini was an even bigger disappointment. It was just a repackaged iPad Mini 2 with Touch ID added (and a new color option: gold).

The iPad Mini 2 wasn't all it was cracked up to be. Photo: Apple.

By contrast, Apple gave the iPad Mini 4 a significant performance boost over the prior models. Most importantly, the screen has received rave reviews. Thus, the new iPad Mini 4 represents a huge opportunity for Apple to start getting iPad Mini users to upgrade.

Apple sold a record 71 million iPads during fiscal 2013: the year the iPad Mini was introduced. A good many of those were full-size iPads -- but even if only half of the year's iPad sales came from the Mini, that still represents a large pool of potential replacement demand.

Do consumers still want iPad Minis?
Of course, none of this matters if iPad Mini owners never plan to upgrade their devices. Many pundits have attributed the sharp slowdown in iPad sales last year to the arrival of the 5.5-inch iPhone 6 Plus. A large iPhone like that could potentially make a small iPad superfluous.

However, the trend of replacing small tablets with large smartphones may be overstated, at least with respect to Apple. Tim Cook has repeatedly stated that iPad usage remains strong. More importantly, the split in usage share between 7.9-inch iPads and 9.7-inch iPads has remained relatively stable at 27%/73% since the iPhone 6 Plus went on sale, according to data from Fiksu.

Many people are still using their iPad Minis. Photo: Apple.

If the iPhone 6 Plus were cannibalizing the iPad, it should have its biggest impact on the smaller iPad Mini series. But while I'm sure there are some people who bought an iPhone 6 Plus and subsequently stopped using an iPad Mini, this isn't a big enough trend to register in the usage data. And if people are still using their iPad Minis heavily, they are likely to upgrade eventually.

The next few months will be key
iPad sales have historically been quite seasonal, with demand peaking around the holidays. Last year, it quickly became clear that the iPad Mini 3 was a flop. Likewise, it shouldn't take long to determine whether large numbers of iPad Mini owners are upgrading to the new iPad Mini 4.

I'm going to be keeping my eye on the relative usage statistics of the original iPad Mini and the iPad Mini 4. Right now, the iPad Mini still accounts for 17% of all iPad usage, while the iPad Mini 4 sits at just 0.3%. If a major upgrade cycle is beginning, we should see those usage shares starting to converge. And of course, I'll be looking out for any comments from Apple's management about iPad Mini 4 adoption.

Adam Levine-Weinberg is long January 2016 $80 calls on Apple, short January 2016 $120 calls on Apple, and short January 2016 $140 calls on Apple. The Motley Fool owns shares of and recommends Apple. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.