Xcode and iOS Updates

it has been another busy week for Apple and iOS developers with new devices and iOS updates. Much has already been said elsewhere but the highlights for me from a developer perspective were as follows:

iPod Touch Retinal Display

I think the new iPod Touch with the high resolution retinal display, gyro and front and back cameras is good news. The resolution of the camera is not as good as on the iPhone 4 but it makes the hardware capabilities of the iPod Touch much closer to that of the iPhone (minus the 3G obviously). This means that if you already put the effort in to update for the iPhone 4 retinal display you will shortly have a much larger set of users who will see the benefit. If you did not already start including support for the retinal display in your apps by default it is probably a good idea to start now.

iOS Numbers

During his presentation Steve Jobs mentioned that they have shipped 120 million iOS devices. Of course the iOS developer agreement now makes is difficult to collect data to analyse that number. So we do not know how many of that 120 million are older devices running older versions of the OS or how many are still active and not gathering dust at the back of a drawer. Either way the target market for iOS developers is huge with Steve claiming over 230,000 new iOS devices coming online every day with 200 apps being downloaded from the App Store every second.

On the other hand with over 250,000 apps in the app store (25,000 are for the iPad) it is increasingly difficult for a small, independent developer to get noticed.

iOS 4.1

As expected iOS 4.1 will ship this week with the GM seed now available for download from the (finally renamed) iOS Dev Center. Since this has been in beta for a while this is not news for developers though it is good that game center will now be live.

iOS 4.2

Again not really news, more a confirmation that 4.2 will be the release that unifies iOS versions and brings the iPad up to date with all of the features of iOS 4. Apple is sticking to a November schedule so I guess we can expect to see a 4.2 beta some time soon.

Xcode 4 Preview 3

The availability of the third developer preview release of Xcode 4 slipped out quietly the day after the Apple music event but for an iOS developer it should not be overlooked (download from the iOS dev center). Since this is all still under NDA there is not much to say. I have played with previous preview releases and will for sure only play with this version. I expect Apple will take their time developing Xcode 4 before giving us a final release. The fact that this is a “developer preview” and not even a beta makes me feel we will not see a final release until next year?

Xcode 3.2.3 and iOS 4 SDK released

Big news today is that Apple has made iTunes 9.2 and the iOS 4 firmware upgrade generally available. This means that existing iPhone and iPod Touch owners will start to upgrade to the new OS. Just as important for developers is that Xcode 3.2.3 and the iOS 4 SDK are now out of beta and available for download. As far as I can tell this is the same software that was previously made available as the GM release. I also assume that this means it is no longer covered by an NDA and we can start to talk about it.

No news yet as to when we might see wider developer access to the pre-release of Xcode 4 (beyond attendees of WWDC).

Which iPhone OS Version should your app support

One decision you need to make when developing an app is the minimum OS version that you will target. Sometimes the decision is made easy if you need to use a feature that is only available in certain versions of the OS. So for example the major differences and additions in iPhone OS versions 3.0 and 3.1 were as follows:

iPhone OS 3.1

Significant additions to the Camera API to support overlays and interaction with the camera. Video editing (3GS models only). A number of important fixes to core data and the NSFetchedResultsController. Additions and enhancements to HTTP live streaming, core audio and core animation.

iPhone OS 3.0

This was a major update from 2.x introducing a huge number of new frameworks and features including Apple Push Notification service, In App Purchase, Game Kit, Map Kit, iPod Library Access, Audio recording, Core Data, external accessory, In App Email, Streaming video, shared keychain items, accessibility support. compass support, OpenGL ES 2.0.

How many people are still using iPhone OS 2.x?

Of course if your app is very simple and does not make significant use of any of the above features you may be tempted to target OS v2.2 as your minimum version. If you do you should consider keeping at least one device at that OS version for testing. However given that the Apple world will soon be moving to OS 4.0 you need to ask if it is worth the effort.

One source of information that is worth considering is the number of people still using the older OS versions. Apple has been pretty successful in getting people to upgrade. Even iPod Touch users who have often had to pay for the upgrades do seem to stay current. The March 2010 Mobile Metrics report from AdMob provides a really interesting breakdown by iPhone OS version:

v3.1.3 - 44%
v3.1.2 - 42%
v3.1.1 - 1%

v3.1 - 3%

v3.0.1 - 1%
v3.0 - 4%

v2.x + 1.x - 5%

So only 5% of iPhone and iPod Touch users worldwide are still using v2.x. If you target iPhone OS 3.0 as your minimum version you will cover 95% of the user population and be able to exploit all the new frameworks that release introduced.

For me the sweet spot right now is iPhone OS 3.1, especially if you are using core data. It still covers 90% of the user population and does not require you to maintain an excessive number of test devices. In fact if you accept the data from AdMob most of your users will be on at least 3.1.2.

It is worth noting that the above data does not include the impact of the iPad and iPhone OS 3.2. However until we see a release of OS 4.x that brings everything back together 3.2 is an iPad specific release. So if you want to cover all angles your best bet would be to build a Universal App targeting OS 3.2 on the iPad and OS 3.1 or later on the iPhone.

As one NDA departs another arrives

So just as the NDA for iPhone OS 3.2 expires Steve announces OS 4.0 and the whole cycle starts again. This iPhone development game is getting to be like a full time job ;-)

Based just on the announcements from Apple today the two most personally interesting announcements were the background services and the iAd service. The background services will not work on older 2nd generation devices which I suspect it as much due to a lack of memory as it is to CPU power.

The use of local notifications will allow a whole class of apps to dispense with a centralised server to do notifications (which could have some impact on third party services like Urban Airship). Would be nice to see Omnifocus use that to show me how many tasks I have due before I open the app.

I wonder to what extent the increased competition coming from Android is driving Apple to iterate more quickly and when we will see new iPhone devices announced?