Apple says iPhone Duo has 100,000-plus optimized apps, but everyday gaps remain

Two weeks after the iPhone Duo went on sale, Apple says more than 100,000 apps built for its foldable are live on the App Store, and thousands more are being added every day.

The announcement on Friday answers the sharpest criticism in the Duo's early reviews, which faulted the $1,999 device for how few apps took advantage of its screens at launch. A new batch of updates arrived alongside the milestone, including Microsoft Word, Outlook, Excel, OneNote and PowerPoint, plus Zoom, Etsy, LTK, Goodnotes, the Halide Mark III camera app and the NBA and NHL apps. Those join earlier adopters such as Netflix, YouTube, Instagram, WhatsApp, Amazon Prime Video and MLB.

"It's been wonderful to see how quickly developers have embraced iPhone Duo," Susan Prescott, Apple's vice president of Worldwide Developer Relations, said in a statement. She added that Apple expects the pace of updates to keep accelerating.

A count that size makes a strong headline. The more useful question for anyone holding a Duo, or waiting for one, is which apps sit inside that number and which don't.

What Apple is actually counting

MacRumors confirmed with Apple that the figure covers apps built with the iOS 27.1 software development kit or later. Those apps stretch across the full width of both the inner and outer displays and move their controls into a vertical status bar.

Everything else falls into two tiers. Apps built with the iOS 27 SDK expand to fill most of the inner screen but stay clear of the status bar along the right edge. Apps built with iOS 26 tools or earlier still run, but they sit in the middle of the inner display, flanked by wide black strips. TechCrunch noted that unoptimized apps can also bury important functions in an overflow menu, which costs more than screen space.

Shoppers can tell the difference before downloading: optimized apps carry a "Made for iPhone Duo" badge on their App Store pages when viewed on the device. Apple is also running editorial collections such as "Popular Apps on iPhone Duo" and "Great Games on iPhone Duo."

The catch is that the 100,000 figure measures which developer tools an app was built with, not how well it works. The Verge pointed to Instagram, which carried Apple's badge at launch but still looked messy to users; Instagram chief Adam Mosseri called the Duo a "bit of a tricky form factor." A badge tells buyers an app fits the screen. It doesn't promise a layout that makes good use of it.

The headline count also runs a little ahead of what owners see. Spotify appears on Apple's list of newly optimized apps, yet TechCrunch said its review unit still showed the black side bar and no update in the App Store. Some of the updates Apple named have evidently not reached everyone.

There are encouraging signs on quality as well. Chance Miller, editor-in-chief of 9to5Mac, wrote that apps that supported the Duo early have since shipped follow-up updates that improve how they handle the inner and outer displays. That pattern of second and third passes matters more than the raw count, because it suggests developers treat the Duo as a target worth refining rather than a box to tick.

The apps still missing

With millions of apps in the store, gaps were inevitable. The ones MacRumors lists are telling, though, because many are daily tools rather than niche titles. Not yet optimized: Venmo, PayPal and Wells Fargo; Google Docs, Sheets and Slides; Microsoft Teams and Microsoft Authenticator; DoorDash, Uber Eats, GrubHub and Starbucks; Delta, Southwest and JetBlue; Duolingo, Libby, Bluesky, Ring and YouTube Music. Apple's own Apple Store app is on the list too.

That mix reveals uneven priorities, sometimes inside the same company. Microsoft has updated its Office suite but not Teams or Authenticator. Google's YouTube is optimized, while YouTube Music and its productivity apps are not. For a buyer who paid nearly $2,000 partly to get work done on a bigger screen, a letterboxed Google Docs or Teams is the kind of gap that undercuts the pitch more than any missing game.

Apple's own Store app trailing behind is a small thing in practical terms, but it is an awkward look for a company asking thousands of outside developers to move quickly.

Why the timeline may work in Apple's favor

Apple says the work is not hard. Apps that rely on standard SwiftUI and UIKit components adapt automatically, shifting controls to the status bar and offering multiple columns on the inner display. New APIs let developers tune layouts for the device's different poses.

Apple has also put in hands-on effort. More than 2,000 developers attended over 50 in-person workshops across 19 cities, where they could use the Duo and work on their apps with Apple's support. That investment, alongside TechCrunch's observation that some developers apparently needed extra time, suggests the transition was less automatic for many teams than Apple's framing implies.

Supply may buy them that time. The Duo sold out within hours of orders opening, and shipping estimates have slipped into next year. On its earnings call this week, Apple said it was "hard to predict" when the constraints behind those delays would ease. That is frustrating for buyers, but it means the installed base will grow slowly, giving holdout developers a window to catch up before most owners have the device in hand.

The same shortage cuts the other way. A smaller audience gives companies like Google or the major airlines less urgency to prioritize the Duo over other work. The next few weeks of updates from those big names will say more about the device's software health than any further milestone count.

Software support is also widening beyond apps. The iOS 27.2 update added support for the USB-C Apple Pencil on the Duo, so owners can sketch in Procreate Pocket, take notes in Apple Notes, Fineliner and TypeDraw, and mark up files in Preview. That pushes the Duo further toward tablet territory, which raises the stakes for the productivity apps that have not yet caught up.

Two weeks in, the trend is clearly positive: big names are updating, early adopters are polishing, and Apple is pushing hard. But the Duo's case rests less on how many apps fit its screens than on whether the ones people open every day, for paying, working and traveling, do. On that measure, the job is well under way and still unfinished.