I might be missing more to the question but an upgrade version of Illustrator 10 would work with any previous version, especially the one right before it. That is why it is called an upgrade.

Thanks for the response. No, I don't think you are missing anything to the question, as the question is simple: can an Illustrator 10 (upgrade) be applied to Illustrator 9 (old) -- when I see a designation as "old" I conclude that it is compared with a "new" version somewhere, and "upgrade" infers there is an Illustrator 10 (regular or some such) which can be "upgraded"; so that brings my question: can Illustrator 10 (upgrade) be applied to Illustrator 9 (old) or does one need an Illustrator 9 (new / regular / or whatever) or Illustrator 10 (regular or whatever) to which an "upgrade" can be applied.

Thanks.

Illustrator 9 is old. Illustrator 10 is old too.

Why is this question being asked? If you have the software in hand, you would know if it upgrades. If you are asking before purchasing an Illustrator 10 upgrade, consider the legal ramifications. Most people selling old upgrade licenses rarely do so legally.

Why don't you upgrade to Illustrator 12 or later?

Thanks.

Why is this question being asked? Because, as with any question, there is an attempt to get an informative answer -- not an evaluation of my motives or commentary on why I don't do this or that.

We'll consider this thread closed.

It is fair to evaluate motives if you are doing something illegal. That would be contrary to the terms of this forum.

Your question indicated a likely license violation, regardless of your intention. We're not here to promote crime.