We support as wide a range of Mac OS X editions as possible. The decision leading to not supporting an older edition is never easy. Finding the best path often comes down to gathering statistics about our customers' needs, and combining that information with a little insight about the feature restrictions any decision will impose.
By supporting older editions of Mac OS X, we frequently need to temper our adoption of brand new Mac technologies. Sometimes we can use them and provide a fallback for older Macs, but frequently this is not possible. So the new technology must remain confined to our research.
I would argue that this tempering should not be viewed negatively. Brand new technologies are rarely perfect and often need a little exercising the in real world before they can be used in critical environments.
Sometimes we conclude that a new technology or framework is just too useful or too compelling not to adopt immediately. This was the case for Power Manager Professional. Professional requires Mac OS X 10.6 and an Intel based Mac.
We were able to make Professional's requirements higher than Power Manager's requirements (Mac OS X 10.4) because of the relationship between the two. Professional creates and manages content that can be used on Power Manager.
A home, school, or business only needs one Mac capable of running Professional to be useful. All the other Macs can run Power Manager on a mixture of Mac OS X editions ranging from Mac OS X 10.4 through to the latest 10.6. Professional creates and manages from the single newer Mac to the many older Macs.
There are significant benefits to supporting older editions of Mac OS X. With every additional edition of Mac OS X a product supports, the more robust your product becomes. Each edition of Mac OS X has its problems, quirks, and foibles. A product spanning multiple editions will need to be crafted to deal with these issues and, more often than not, be written in a more defensive manner.
There are costs to supporting older editions of Mac OS X. You only need to glance at Power Manager's multiple package installer to understand that it is not a clear case of one size fits all Mac OS Xs. Some files are needed for some editions, other files are needed for other editions. While the installer shields you from these quirks, there is always a human having to build those installer packages. Gaining the knowledge of how each Mac OS X differs takes time, takes testing, and takes a long view over the direction of the Mac operating system.
Our testing rig at DssW is currently at a high point. Five years ago, Apple made the transition from PowerPC to Intel based processors. This transition means that our customers currently have an impressively diverse mix of Macs in active use.
The mixture ranges from single-core 32 bit PowerPC Macs to multiple-core multiple-processor 64 bit Intel Macs. Throw into this mix the various editions of Mac OS X that are in use, and suddenly the testing rig required becomes a sizable problem.
Is all this effort worthwhile? Yes, because our work can be used by more customers, on more Macs, in more environments.