... ... but not if you have any files created using earlier MacDraw from AppleWorks, or even ClarisWorks: none of these files can be opened using the iWorks downgrade!10.5 is DEFINITELY worth the upgrade
But if you haven't yet disposed of your earlier hardware/software, just refuse to let the next owner have the software that goes with the computer. It won't work then, of course, but you can just laugh at the poor fool who trusted Apple to read earlier Apple files. Just like Apple laugh at their customers.
They won't sell you a program that opens previously saved files, and won't open them for you, either. HaHa! Then you might be able to save them in another format and continue using your resource material sir, or read material submitted to you in the earlier format (i.e. up to 10.4).
Never mind. There are always second-hand shops..