Apple's foldable iPhone Duo hits stores as reviews flag unready apps

Apple's first foldable iPhone, the iPhone Duo, went on sale in stores on Friday. It enters a field where Samsung already sells the Galaxy Z Fold 8, which Engadget used as a weight comparison in its review.

Early reviews are mixed on value. Engadget rated it 8.8 out of 10, while 9to5Mac said a regular iPhone is still the practical choice for most people.

Key facts

• The iPhone Duo starts at $1,999, according to Engadget.
• It has a 5.4-inch outer display and a 7.6-inch inner display.
• It uses Touch ID in the side button instead of Face ID and has no telephoto camera, 9to5Mac said.
• It weighs 254 grams, or 8.96 ounces, Engadget reported.
• TechCrunch reported that many mainstream apps were not optimized by launch day.

Background

The Duo is Apple's first folding phone. Engadget compared it with Samsung's Galaxy Z Fold 8 and found the Apple phone more than 25 percent heavier.

The Duo also breaks with recent iPhone design. Apple's flagship phones had relied on Face ID since the iPhone X in 2017, and the Duo returns to a fingerprint sensor.

Design and hardware

The Duo opens like a book. Engadget says the outer OLED screen measures 5.4 inches with 120Hz ProMotion, and the inner screen measures 7.6 inches.

Apple says the inner display is 50% larger by area than the iPhone 18 Pro Max's, and the largest ever on an iPhone, 9to5Mac reported.

The phone is built to be tough. Engadget says it is rated IP68 for dust and water resistance and uses a titanium frame. 9to5Mac says it comes in Night Sky and Star White, with a Grade 5 titanium frame.

It is also heavy. The Duo weighs 254 grams (8.96 ounces), which Engadget says is more than 25 percent heavier than a Galaxy Z Fold 8. 9to5Mac says it is five grams heavier than the iPhone 18 Pro Max.

Inside, the Duo runs on the A20 Pro chip, the same chip used in the iPhone 18 Pro and Pro Max, according to 9to5Mac.

Trade-offs

The Duo gives up some features found on Apple's top phones. It uses Touch ID built into the side button instead of Face ID, and it has no telephoto camera, 9to5Mac said.

Battery and charging

Battery life tested well. In Engadget's video rundown test, the Duo lasted 28 hours and 48 minutes.

Apple says the phone can charge to 50 percent in 20 minutes with a 60-watt adapter. Apple also says a 45-watt charger is enough to reach top wired charging speed, Engadget reported.

Apps are still catching up

Software is the biggest weak spot so far. TechCrunch reported that many mainstream apps were not ready by launch day, showing black bars or oddly placed controls.

Engadget found that unoptimized apps such as Telegram show a portrait layout with dead space on the inner screen.

Some developers moved fast. TechCrunch said Netflix, the MLB app, NYT Cooking and Slack had apps built for the Duo when it shipped. Engadget names Netflix, Instagram and OpenTable as already adjusted.

Others built new features. TechCrunch reported that Flighty added an En Route Mode for the Duo's tent position, and a retro computer app offers 10 vintage computers for a $3.99 one-time fee.

What reviewers said

Reviews differ on whether the price is worth it. Engadget gave the Duo an 8.8 out of 10 score but listed heavy weight, high price and many unoptimized apps among its cons.

9to5Mac was more cautious. It said that at $1,999, the Duo is an expensive proposition, and that a traditional iPhone is still the practical buy for most people.

What it means for you

Buyers comparing the Duo with the iPhone 18 Pro give up Face ID and a telephoto camera, 9to5Mac said. In return, they get a much larger inner screen.

People who rely on certain apps may see rough edges for now. Until developers update their apps, some may not fill the inner screen well.

Practical steps

• Check your apps. See whether the apps used most have been updated for the Duo. Engadget lists Netflix, Instagram and OpenTable among those already adjusted.
• Plan for charging. Apple says a 45-watt charger is enough for the fastest wired charging, Engadget reported.
• Weigh the trade-offs. The Duo lacks Face ID and a telephoto camera, according to 9to5Mac.

What happens next

Reviewers expect more apps to be optimized over time as developers release updates, Engadget reported. Sales figures and any shipping delays have not been reported.

FAQ

How much does the iPhone Duo cost? It starts at $1,999. Prices for higher storage tiers were not confirmed.

Does the iPhone Duo have Face ID? No. It uses Touch ID in the side button.

How big are the screens? The screens measure 5.4 inches outside and 7.6 inches inside.

Is it heavy? It weighs 254 grams, five grams more than the iPhone 18 Pro Max, 9to5Mac said.

How long does the battery last? In Engadget's video test, it ran for 28 hours and 48 minutes.

Is it water resistant? Yes. Engadget says it carries an IP68 rating for dust and water.

Are apps ready for the bigger screen? Not all of them. TechCrunch reported that many mainstream apps were not optimized at launch, though Netflix, Slack and others were.

Can it charge quickly? Apple says it can reach 50 percent in 20 minutes with a 60-watt adapter.

What colors does it come in? 9to5Mac says it comes in Night Sky and Star White.

Which chip does it use? The Duo uses the A20 Pro, the same chip as the iPhone 18 Pro models.