I’ve seen a few articles lately on the file incompatibility between iWork ’08 and files saved in iWork ’09.
Macnn and other sites have discussed it. As usual, there are the silly comments regarding Apple not having tested this, it’s worthy of Microsoft, blah, blah, blah. Many comments tended to be more rational, though, pointing out that new versions of software frequently “convert” older files and then are not compatible with the older version. This isn’t really that unusual.
I think Apple could have made this easier if they had explained in the tech note a primary reason for the incompatibility. It’s the old standard support line: It’s a feature, not a bug. Really.
The iWork ’08 saved files are packages. For those unfamiliar with this, a package is essentially a specialized directory (yes, I’m simplifying it). Most Mac applications are packages, as is the iPhoto library. If you right-click a package file and select “Show Package Contents,” it’ll open like a folder to reveal other files and folders below. Here you see the package contents of a Numbers ’08 document.
The problem with this approach comes when you want to transfer these files. Some email systems or file shares don’t know what to do with a package file. For example, when I look at iWork ’08 documents in Windows they appear as folders. In short, the package format was hindering transfer and sharing of iWork files. Not good if you want your product to become more popular.
Enter iWork ’09, which saves documents as a more traditional “flat” file. Apple’s implementation of this is that the file is still a package, but compressed into zip format, which makes it flat. In fact, you can see this for yourself by changing the file name’s extension to .zip, then decompressing it by double-clicking. The uncompressed file will be a folder containing some files/folders like you saw in the iWork ’08 file. (As you can see, it’s not an exact match, so some data appears to be stored in the file itself.)
As a flat file, you should be able to email it and share with other iWork users without problems. iWork ’09 opens it easily, knowing it’s compressed and handling it accordingly. iWork ’08, however, is expecting a package file; it doesn’t know what to do with the flat file iWork ’09 uses. This is why it cannot open those files.
I think Apple really needed to address the package issue for transporting iWork files, and I’m glad they did so in iWork ’09. It neatly addresses a problem that was only going to get worse as the package became more popular. I don’t think having a new version not opening in an old version of the program is that egregious, especially given the problem the new version is addressing.