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Choosing big cats

LeopardWhenever a developer does a major new release, one of the many issues that they need to consider is which OS versions to support. It's always a tradeoff: having the apps continue to work with older versions allows more people to use the product, whereas the more it is restricted, the more new OS features can be leveraged.

Let's explore the second point first. Each time Apple does an OS upgrade, they make some cosmetic UI changes, add new bundled apps, and so forth, but they also introduce new or improved development frameworks, APIs, and tools. For example, in Tiger (10.4) Apple introduced Core Data, a sophisticated database-driven data modeling and storage API, among others. While it is possible to use some new functionality by checking for its availability, some are more fundamental, so just have to be done without to maintain support for older OS versions.

Apple's Non-Disclosure Agreement forbids me to talk about the new features in their upcoming OS, Leopard (10.5), other than what has been publicly announced. But it should be clear from the available information that Leopard is one of their most significant OS updates, with numerous UI changes, and for developers, Objective-C 2.0, which includes fundamentally different memory management and other improvements.

Being able to leverage the new technologies in Leopard will offer a huge advantage in terms of the features that can be added, and the efficiency of the underlying code. To maintain compatibility with Tiger, a developer would either have to forgo these features, or write lots of code to emulate them. Certainly doable... but is it worth it?

That brings us to the other side of the equation: how many people would benefit from a release that supports an older OS? Thankfully, history provides some guidance. Of course, it should be pointed out that every market is different, and people find software in lots of ways. Lots of people, probably the majority, just pick up a few boxed software products when they buy their Mac at a local Apple store or other retailer, and never explore beyond that. They only need a few core apps, many of which come bundled with the Mac, and that's all they want.

While I'd love to bring my products to the attention of these people, the ones that most interest me are those who actively seek out third-party indie apps to enhance their Macs. This subset tend to be early adopters, often upgrading their computers every few years, and thus getting the new OS then, or they go out and buy the OS as soon as it is released, or perhaps after an update or two, to ensure it is stable. In fact, one could hypothesize that there is a strong correlation between the speed of upgrading the OS and that of upgrading third-party apps. Or put another way, if someone isn't interested in keeping the OS up-to-date, they are probably less interested in keeping third-party apps up-to-date, or even trying third-party apps.

I have tracked OS versions of people using my products, as many other developers do, and these numbers support this hypothesis. For fascinating interactive charts showing the OS versions and other attributes of the Omni Group's customers, see their update charts.

So, there seems to be little benefit in maintaining support for older OS versions, and several benefits from being able to leverage the new technologies.

As for my own products, I do plan to require Leopard when I next do major upgrades of each product, but they will be phased in over time. I will continue doing updates that support 10.3.9 and later in the meantime. Even after the major upgrades, the older releases will continue to be available for customers who aren't ready to upgrade their OS. Hopefully that will keep most people happy, while allowing me to move forward.