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Posted by CameronBanga 4 days ago

Xcode 27.1 Beta Release Notes(developer.apple.com)
154 points | 116 comments
yreg 4 days ago|
Finally! So we have a little over a month between getting the simulator and first customers running our apps in Duo.

I expect that most apps will look rather broken on release, but it will be smoothed out eventually.

gyomu 4 days ago||
Apps that support iPad are 95% fine unless you do crazy custom things (which Apple has been telling developers for decades now that they shouldn’t do), and apps that are phone only are letterboxed, but still entirely usable.

How many customers do you expect to be running on Duo for the first year of its existence?

I’d be surprised if it was >0.01% for anyone. Apple wants you to drop everything to support all the bells and whistles for their new device, but even if you take 3 months to fix minor layout bugs, I don’t think it’s that big of a deal.

I have friends who dropped everything to support the Vision Pro, and I don’t think any of them felt like it was worth it in retrospect. Even the ones that got featured by Apple as a result didn’t see more than a few thousand downloads.

addaon 4 days ago|||
> How many customers do you expect to be running on Duo for the first year of its existence? I’d be surprised if it was >0.01% for anyone.

How do you figure? Assume the average Apple cell phone replacement cycle is somewhere between 3 and 4 years. At the longer end, you’d need the sell-through rate of the Duo compared to other phones to be less than 0.04% to hit your number. We know from the Mini and other phones that Apple tends to avoid designs that it expects to have less than a 5% sell rate, two orders of magnitude higher. Even if you assume they’re aiming for 5% of dollars instead of units, and you take into account the non-Apple market (which certainly should not be unit-weighted for folks thinking about app revenue), you’re off by well over an order of magnitude.

ulfw 4 days ago||
If he is off by an order of magnitude and it's 0.1% still no developer (unless a fanboy) should bother
addaon 4 days ago|||
Why? If you’re spending 2000 hours a year servicing your current customers, surely it’s worth 20 hours to add on 1%, even ignoring that that 1% is probably more valuable than your average customer, and the halo effect of giving a good experience to existing users migrating devices.
Grombobulous 4 days ago||||
Although maybe they should because someone willing to buy a $2000 phone on launch is probably more willing to buy a lot more things versus someone who keeps phones a long time.
astafrig 4 days ago|||
What does being a ‘fanboy’ mean in this context?
matwood 4 days ago||||
Usually just compiling with the new SDK will get apps basic support if they have been following Apple standards.

> I have friends who dropped everything to support the Vision Pro

The VP was a niche device for a niche market. Phones are not that. I think the Duo will do very well. The one knock are the cameras do not match the Pro. I don't think will care though.

wahnfrieden 4 days ago||||
Apple does many crazy custom things in their own apps. Their advice is not sacrosanct. It just means you must prepare for less notice than they had if you want to compete with the frontier UI aspects that Apple apps achieve.
AdamN 4 days ago||||
> I have friends who dropped everything to support the Vision Pro, and I don’t think any of them felt like it was worth it in retrospect. Even the ones that got featured by Apple as a result didn’t see more than a few thousand downloads.

They should remember that they got quite a bit of social capital within Apple by doing that and hopefully they're keeping those relationships warm. But yeah Vision Pro hasn't turned out to be a big ecosystem so far.

AceJohnny2 4 days ago|||
> a bit of social capital within Apple by doing that and hopefully they're keeping those relationships warm

That social capital and $5 will buy me a cup of coffee.

grey-area 4 days ago|||
Because Apple has always treated its developers so well!

Vision Pro will be cancelled at some point, it’s just nowhere near popular enough and never will be - the air has gone out of that VR bubble.

I wouldn’t be surprised if duo is also cancelled because it is another copycat move which is not central to Apples business and will not be mass market.

user43928 4 days ago||
It's going to be mass market and I wouldn't be surprised if it sells out on launch day in the US.
grey-area 3 days ago|||
I don’t think a $2k phone is anywhere near mass market, esp given the likely downturn ahead.
setopt 4 days ago|||
Based on what? At that price tag, I doubt it will be mass market, but perhaps I’m wrong.
user43928 3 days ago||
So far I have seen mostly positive reactions.

I believe there is a large market of consumers in the US who can afford a $2000 premium phone compared to the $1300 iPhone Pro Max.

In China, reportedly JD.com's Apple store received more than 1.13 million registrations of interest for the Duo, at a starting price of ~$2400.

I could be wrong also, but I wouldn't be surprised if the iPhone Duo sells like hot cakes.

I could imagine that premium smartphone buyers, instead of upgrading their phones for minor camera and battery improvements, go for the device that unfolds into a tablet.

AdamN 2 days ago|||
Yeah I think East Asia will drive alot here. That's where the large screen phone trend started as well. I'm also suspect of a $2k phone that also has had to make a number of compromises to support the new format. But the market will tell us who's right and it was worth it for Apple to try. If they fail it's really not the end of the world and they can pivot back to traditional form factors or find another.
setopt 2 days ago|||
Interesting, thanks for the explanation. Especially the China argument is promising.
etatester 4 days ago|||
> apps that are phone only are letterboxed, but still entirely usable

How is that possible? iPhones have had varying screen sizes for more than a decade, how could any app still have a fixed size?

basisword 4 days ago|||
Because despite Apple having clear guidelines a huge number of developers think their 'custom UI' is what customers really want. When they don't. The best apps use system components and follow the HIG. Always have, always will. Your custom tab bar is stupid.
bartvk 4 days ago|||
There are many. We have an online supermarket with an app (Picnic) who don't support iPad, don't support landscape, don't support dark mode, etc.

I bet it's due to product managers not caring about those.

james_pm 4 days ago|||
Fired it up to check my own app (RunnerCast) and it looks fine. The Liquid Glass menu moves from the bottom to the right side automatically both on the inner and outer screens. If you already had a layout that worked for iOS and iPadOS, things adapt fine to the inside screen and when you go split screen with two apps, the layout adapts nicely. I don't think I'll need to do a thing.

I've also noticed a flurry of recent app updates from some of the bigger apps (MLB, NYTimes, etc.) to switch to the Liquid Glass menu which I assume Apple strongly suggested they do prior to the Duo launch.

yreg 4 days ago|||
> some of the bigger apps to switch to the Liquid Glass

Interestingly, Instagram decided to implement a custom liquid-glass like tab bar which surely now turns to be a PITA.

1f60c 4 days ago||
It also happens to look ugly AF. Even WhatsApp gets it right.
kccqzy 4 days ago||||
It’s really interesting to note how the bigger apps deferred adopting Liquid Glass altogether until iOS 26 is out for almost a year. Do most developers making large apps also loathe it? Do they have in-house designers telling them not to adopt it?
earthnail 4 days ago|||
It breaks most design languages. It’s not a neutral element.
wahnfrieden 4 days ago|||
It’s a lot of work
shantara 4 days ago|||
iOS 27 SDK will ignore the liquid glass compatibility flag, so the developers are now being forced to adopt it, unless they choose to stay with an old SDK version and all the hassle it brings.

https://developer.apple.com/forums/thread/832710?answerId=89...

reaperducer 4 days ago|||
I expect that most apps will look rather broken on release, but it will be smoothed out eventually.

Sadly, many apps will continue to look rather broken.

There are still thousands of apps that still look wrong on iPad 16 years after its release, even with the 2x button pushed, for no good reason.

I think I heard that Instygram only recently figured it out.

pkamb 4 days ago|||
Instagram released a Reels-first iPad app that is much, much worse than the old iPhone-on-iPad app.
basisword 4 days ago||
They finally released the full experience a few months back. I think their original excuse (years ago) was that 'people take photos on iPhone so iPad is unnecessary for Instagram'.
c-hendricks 4 days ago|||
To me that's said more about Instagram than the feasibility of building an app for a tablet.
alwillis 4 days ago|||
> I expect that most apps will look rather broken on release, but it will be smoothed out eventually.

I don’t think it'll be "most apps".

Apple all but told developers in June [1] to update their apps not to assume a fixed screen size.

One of the apps Apple's engineers demonstrate new features was called Origami [2]. When I watched the video, it seemed pretty clear: a device that folds was in our future.

If you’re a developer that's kept up with the latest iOS developments, you'll be in good shape for the Duo.

But if you're up to your eyeballs in technical debt using deprecated frameworks and APIs… it's probably gonna be a while for you.

[1]: https://developer.apple.com/videos/play/wwdc2026/278

[2]: "Modernize your UIKit app" — https://en.wikipedia.org/wiki/Origami

bartvk 4 days ago||
Also, every iPad has a full window server. So any app that was available for iPad, should've been resizable in any shape.
comandillos 4 days ago|||
"You are a experienced iOS Software Engineer, your task is to migrate this application to the iPhone Duo layout...
thih9 4 days ago|||
“Here is your iOS app migrated to Surface Duo…”

Tongue half in cheek, my point is that agents may be unreliable with fresh libraries.

It looks like there are some fun edge cases too:

> A reserved region can be active or inactive. For example, a reserved region that represents the fold is active when iPhone Duo is partially open, but inactive when it is fully open.

source: https://developer.apple.com/documentation/technologyoverview...

CharlesW 4 days ago|||
> Tongue half in cheek, my point is that agents may be unreliable with fresh libraries.

You may find Axiom (my FOSS project, updated for iPhone Duo) helpful. https://charleswiltgen.github.io/Axiom/

Note: I'm scrubbing it against the final 27.1 beta SDK as I type this, so it's likely that its Duo knowledge will get an update within the next few hours.

matthewfcarlson 4 days ago|||
Fun fact, I’ve now worked on the surface duo (technically the windows version not the android version) and the iPhone duo.

I thought the ideas of the surface duo were great and I’m super excited to see them evolved and shipped in a product that I think a lot of people are going to love.

yreg 4 days ago|||
Yeah, good luck with that.
pjmlp 4 days ago|||
Unless Apple uses their stick (whip, or whatever else) to drive the developer community, I bet iOS will experience the same app fragmentation as Android does regarding various form factors, more so than between iPad, iPhone and iWatch already.
alexashka 4 days ago||
Most apps people actually use will look fine because there's a team of mobile devs in all big companies who get paid to keep up with Apple breaking their apps every year with their 'updates' (among other things).

I mean, don't expect advanced features like consistent smooth scrolling, non-broken UI, absence of animation flickers, cloud sync that works consistently even for paid apps developed by Apple or anybody else but other than that :)

yreg 4 days ago|||
In plenty of big companies one month is not even enough time to get a new release into production, let alone test and fix the layouts.
alexashka 4 days ago|||
You're right.

My brain must have blocked out the 'cadence' (oh the corpo speak!) of corporate dev out of self preservation.

delian66 3 days ago|||
Why is that?
makeitdouble 4 days ago||||
This is the first time we get an iPhone skew that is significantly different and with no sales track record.

For instance, very few company bothered to do anything for the Vision Pro. Now we'll see if Google or Microsoft for instance see the iPhone Duo as a main line product or an exotic offshoot that needs to prove itself before any money is spent on it.

ulfw 4 days ago|||
None seem to be working at Meta.

How many years has it been for them to release an upscaled (zero extra features!) version of instagram and whatsapp for iPad?

Two of the most used apps in the world

Austin_Conlon 4 days ago||
Apple also bundles a /uikit-app-modernization skill which should help with adopting layouts to iPhone Duo.
TheJoeMan 4 days ago|
Apple’s Developer Documentation is historically pretty terrible. So I’d be curious to see if they stepped it up for the agent instructions for the new API’s.
ChrisMarshallNY 4 days ago|||
> historically

Depends on how far back you go.

Apple's current docs suck, and they have, for a long time (SwiftUI was so bad, that someone came up with this[0], and it was a lifesaver).

But I'm old enough to remember Inside Macintosh[1], and that was a thing of beauty.

Apple used to take technical documentation very seriously. Many of their technical writers had better tech chops, than the engineers making the stuff they wrote about.

[0] https://swiftui-lab.com

[1] https://vintageapple.org/inside_o/

LoganDark 4 days ago||
I really wish they still did, instead of focusing so much on trying to make it simple and obvious like in SwiftUI. Objective-C was a pinnacle of computing, and ever since Swift they've been devolving into the pursuit of oversimplifying and abstracting away the details such that they don't even feel necessary to teach anymore, even though as a new developer, I WANT TO KNOW THEM.
matwood 4 days ago|||
> Apple’s Developer Documentation is historically pretty terrible.

Historically it was very good. Back when I was writing Mac and iOS apps in objective-c, Apple's docs were some of the best.

Shank 4 days ago||
I've been testing with Xcode 27.1 on the Duo simulator and I was pleasantly surprised that nearly everything worked well, untouched. The main thing I need a real device for is knowing which buttons are easier or harder to press on the right edge, but using modern UIKit this was not that difficult. That, and taking advantage of the left/right inner display content areas.
ar_lan 4 days ago||
I think this is my main hesitation with picking up the Duo on the first release. I have no doubt the build quality is exceptional, but the chance that the apps I use are not well optimized for this new form factor is pretty high in the first year of its release.

I don't think they won't work, but I anticipate oddities to appear for a while, especially for older applications.

puelocesar 4 days ago||
I’m not sure about this, we already support resizing on our app for a while now because of our iPad/mac catalyst version, so I fail to see how different it would be on the Duo.

I assume other apps will have have the same, since our team is super small compared to everyone else.

Kwpolska 4 days ago|||
The small screen is so small they had to move controls to the right, I would expect glitches because of that, especially for custom controls.
puelocesar 4 days ago||
Ok, I’ll test that, but I think we are using the safe areas correctly
madeofpalk 4 days ago|||
Apps not rebuilt with the latest SDK will display in pillar-boxes mode, centred on the screen.
josephg 4 days ago|||
This is my feeling too. It looks great - I think I might pick one up. But I’m going to give apple a few years to iron out the bugs first. Version 3 of the duo will be a much better product than version 1.
ulfw 4 days ago||
Version 5 is when it'll be actually competitive.
CameronBanga 4 days ago||
Now available for testing apps on the iPhone Duo!

Here are some screenshots from getting my own app compiled, if anyone is interested:

https://bsky.app/profile/cameronbanga.com/post/3mvsrxk5q7b2j

https://bsky.app/profile/cameronbanga.com/post/3mvss5wmxej2l

OCTAGRAM 4 days ago||
I presume this Xcode 27.1 beta will not want to launch on our Mavericks Forever, the last Mac OS we actually like and use.
CharlesW 4 days ago|
Correct.
interpol_p 4 days ago||
I started adding support for iPhone Duo in some of my apps. Here's an example of some of the work required https://mastodon.social/@simsaens/117296064810231465 — all my apps are hobby apps. Even though they all support iPad / resizability, it's still a large amount of work
phillipseamore 4 days ago||
Looks like Safari 27.1 on Duo ships without support for CSS viewport segments and any other CSS or JS to handle foldables.
bartvk 4 days ago|
I'm not a webdev, is that surprising? Or is it more something that you would have wanted or expected?
phillipseamore 4 days ago||
Certainly, these aren't new standards and have been available on Android. We like to offer a split page when a foldable is used in a book pose and avoid having anything (especially interactive elements) in the middle.
tehnoslow 4 days ago||
Thanks for Axiom, looks useful. Does it already cover the new 27.1 beta APIs?
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