I did a search here already, and haven't found a clear answer to my question, so I thought the time was right to post.
I have an iOS application that was developed using Xcode 3.2 and SDK 4.2. When I built the bundle, I targeted iOS 3, so that people running older iPhones (like my wife who has iPhone 3 with iOS 3.x on it) can run the application. The app was also tested on, and runs fine with, the latest 4.x iOS.
With the release of iOS 5, I want to make sure my app is compatible. There is nothing new in iOS 5 that my app uses. I have installed the latest version of Xcode and iOS SDK. My question is this : if I rebuild my app using this new Xcode/SDK combination, and set the target iOS level to something older than 5, for backwards compatibility, this still means that my application is built for, and is thus compatible with, iOS5, correct? I will of course test it with iOS 5, but I want to be able to claim it's supported on iOS5, while still maintaining backwards compatibility.
Do I understand correctly how this works?
Thanks!
Mark
Yes, that's no problem. You should always build with the latest SDK but if you set your Deployment Target to, let's say, 4.2 (which is common for many apps), or even 3.0, as you intend to do, of course it will run under iOS 5.
Testing it will still be wise since there are some changes that might lead to bugs in iOS 5, but in general, it shouldn't be a problem.
Related
We are planning for a new mobile application for iPhones/iPads this month and we are outsourcing this project as we dont have much knowledge about the subject. Could someone tell me if current iOS applications will run on iOS 7?
I would appreciate help in this as I tried to search but could not find related articles as most of the articles talk about features and not backwards compatibility.
Sure. It will support older versions of iOS. If not millions of applications in Appstore will be unusable in iOS 7. You need to download iOS 7 SDK once available to exploit iOS 7 specific features, thats all.
Yes current iOS application will run on iOS 7, because apple will take care that if they launch new iOS then they create new iOS in such a way that it's always compatible with older iOS apps other wise if someone upgrade the iOS and the apps of previously developed will not work on it then they loose their customers/users. So don't worry new iOS 7 will also support apps developed for iOS5/iOS6. There were only new features in iOS7.
Although iOS 7 has seen a major overhaul in UI field as well as several back end changes too. But the main point for your question is that any application if working on previous versions of iOS should work in iOS 7 too. The OS will take care of all the UI instances drawings in different versions of OS. The situation where the applications supporting newer versions of OS not working on older versions is that they use some features only available to a specific version of OS or later.
It would run in iOS 7, but probably not as you would expect it to run, so my recommendation is to create 2 (or 4 if you build for iPad) 1 for iOS 6 - and one for iOS 7 + just detect the iOS version and load the storyboard for the appropriate version
It is always better to start development in the latest available version of iOS. In this case 7 is the latest with all the support for developers. You can get the relative iOS SDK and Xcode.
Long Story Short: Start Development in the latest iOS and nothing shall go wrong.
From the research I had done, indeed app built using 6.1 SDK and Xcode 4.6 will run on iOS7, however, the app will have an iOS6 look and feel on iOS7.
How can i check the compatibility of my application, based on IOS 5.0.1 created with Xcode 4.3.3 on Lion, on IOS 6 without having to change my current MAC OS version and Xcode? Is there any way? And as an addition to this question, if i submit my application to the Apple Store, can it be rejected just for the simple reason of being created compatible with IOS 5 and not with IOS 6.
It’s not clear what you mean by “compatible”. One thing is the version of the SDK you link against, one thing is your Deployment Target setting and then there’s actual code compatibility regarding various API, UI and behaviour differences between iOS 5 and 6.
It seems that you have to develop with at least the iOS 6 SDK to submit your app at all.
However, your Deployment Target setting may go as low as required, so that your app still supports older iOS versions.
Your app doesn’t have to be “compatible” with iOS 6 in the sense that you tested it on iOS 6 and handled all the potential quirks that may have appeared by moving from iOS 5 to iOS 6. Of course, the user experience on iOS 6 could suffer in this case, but unless there’s a major bug, the reviewer doesn’t care.
I am writing an iPhone app in which I want to support the largest user base possible at this point in time (with minimal pain), so I decided that targeting IOS 4.3+ would be a good subset of users for my audience.
I started working in XCode 4.2, but reverted back to XCode 4.1 when I realized that the project templates had changed and everything seemed very intertwined with storyboarding, ARC, etc.
I have built out my application to the point I actually want to test on my device, which has iOS5 installed. When I attempt to use it though, I get this message as soon as I click 'use for development' in Organizer/XCode:
The project's build settings look like this:
My Question Is This: How do I get this application, built in XCode 4.1, to run on both iOS 4.3 and iOS 5 phones?
Are iOS SDKs not backward compatible? I come from Android development in which a less than current SDK will generally work on a newer SDK - is this different in the iOS world? And if so, how is this handled typically?
Any direction on how I should proceed would be greatly appreciated.
You can go ahead and open your app in Xcode 4.2 and it should still work. I've been working on a particular app since Xcode 3.x days and I'm nearly done, chugging along in Xcode 4.2 right now. It shouldn't be a problem. If you want to work with Xcode 4.1 you will be fine, but you won't be ale to use new features introduced in iOS 5.
There are several aspects of "cross-version" development to note.
Testing: You can only test on version of iOS that are included with your SDK, or that are installed on physical devices that you may have. The SDK generally comes only with the latest iOS, sometimes the previous one is included as well, but since Xcode 4 was released, the older SDKs have been progressively deprecated with each release. This is not to say that your app which is linked against the iOS 5 SDK won't run on older versions of iOS. It just depends on how you implement new features.
Features: In order to support older versions of iOS properly, you want to make sure that you don't implement new features without properly checking for the existence of classes, methods, and properties that were introduced in the newer versions of the OS. Unlike Android, you don't have to worry about a million hardware configurations. ;-)
Weak Linking: To support a new feature and still be compatible with older versions of iOS, you need to weak link against frameworks that you are using to implement new features. You can read more about that in the Apple Documentation on Weak Linking.
Deployment Target: The setting that prevents the app from loading on older devices is called the "Deployment Target". If you set this to 3.1.3, then your app will run on iOS 3.1.3 and higher. Remember that if you don't code the the proper version checking, your app may break.
ARC: You can choose to enable or disable Automatic Reference Counting when you create the project. ARC scans your program at compile time only, not at runtime, it doesn't break the app on older versions of the OS.
You need the latest version of XCode and the iOS SDK to install your apps onto your iOS 5.0 phone. That doesn't mean the inverse is true -- you don't need the same version of iOS on your device that you have installed on your computer.
Hope this helps!
You can use the latest SDK and simply set the "IOS Deployment Target" version to 4.3 in the project build settings.
XCode 4.1 doesn't support iOS5 in the sense that Xcode package doesn't contain the iOS5 SDK. So you must return to Xcode 4.2 and target your project for iOS 4.3 (you can also target it for iOS 4.0 with this Xcode version, but you will not be able to simulate it; you can even download older iOS 4.x package versions from the Xcode preferences menu if you really need to simulate them in your device).
You can opt-out of ARC if you want, this choice is given to you when you create the project, so don't worry; but consider that ARC does its magic at compile time only, not at runtime, so your backward compatibility will be kept if you decide to use this technology. Finally if you don't want Storyboard just pick the Empty app template and it will simply put in your project only the basic files. From this template you can create any iOS app, this is the approach I normally follow.
I am a beginner Apple developer and I have some issues I would like to resolve.
First of all, I am curently working on Xcode 3.2.6 because I haven't enrolled for the developer program yet. I would like to know if Apple only accepts apps (for the App Strore) compiled on SDK 4.
Secondly, I want my apps to work both on iPhone 3 and 4. What would you advice me to do? I have read in several developer forums that in order to achieve this I have to build my application with 3.1 iOS as a target. Is this correct?
Finally, is there any problem due to the difference in resolution between iPhone 3 and iPhone 4? Which resolution do you think I should use?
Thank you in advance,
Cherry
Set Base SDK to latest (4.3).
Set Target SDK to 3.1.
Avoid features available only in iOS 3.2 or later (e.g., don't use blocks, don't frameworks introduced in iOS 3.2 or later, always check availability of methods). Later, when you get more experience with Objective-C, you may try to combine features of more modern iOS, but still keep compatibility with older iOSes.
Don't worry about resolution. It affects only images – if you want to take full advantage of Retina display, then you will need to create images for both resolutions (std. and hi-res).
P.S. I suggest you to avoid support for iOS 3.2 or earlier. iOS 4 introduces a lot of nice and helpful features. And I pretty sure, Apple will revoke support for iOS 3.x soon after iOS 5 release.
If you are aiming for iOS 3, you will end up not using the features of iOS 4, which is the majority.
This is Apple's statement.
Target the latest iOS release.
Targeting the latest release allows you to take advantage of all the features
available in the latest version of iOS. However, this approach may offer a smaller
set of users capable of installing your application on their devices because your
application cannot run on iOS releases that are earlier than the target release.`
Target an earlier iOS release.
Targeting an earlier release lets you publish your application to a larger set of
users (because your application runs on the target OS release and later releases),
but may limit the iOS features your application can use.`
But I would suggest that you target the iOS 4 as people are now targeting iOS 5, and in another 8 months, I am sure Apple would release iOS 6 (They are very quick with their updates), and I personally feel that targeting iOS 3 is not going to give you great results in the long run.
We are about to issue version 4.0 of our iPhone app and have had some complaints recently that previous versions are only available from iOS 4.1 plus. I know that to change this I can set my Deployment Target (In Project>Build) to iOS 3.1. However, I've run through the app on an emulator and again on my iPhone (uses iOS 4.2) but I'm not able to test on anything older as everyone here has the same iOS or 4.3. Can I safely assume that just by changing the Deployment Target and testing the app on later models that the app will run safely on later versions like 3.1.
We are familiar with the reason why people with older iPhones wont upgrade to iOS 4.0 and above, so we would like to accomodate them but not if it means the app is unsound and we have no way of testing it.
No, just because it compiles and runs on newer version of the SDK does not mean that it will work on older versions. If you're using features that are only available in iOS 4+ you'll need to check for their existence before using them; your app will crash otherwise.
There are some subtleties that you'll probably miss the first time too (or at least I did). In short, there's no real alternative to testing.
for the problem you have you need to install older versions of xcode having ios 3.0 support and you need to check whether it's working on the same or not as there are lots many changes in os 4.0 and above so it's definite that the application will not work with the ios 3.0, 3.1 available device and it will crashed.
Just install older version of SDK and test on simulator , if works then fine else you need to make code according to ios version 3.0 and ios version 4.0 in your code by differentiating the os and run the code accordingly.