How to Open Illustrator (Ai) files or EPS files in version of older versions.http://www.stokesdesignproject.com/down-save-illustrator-file-service.php.

• Generally chances are better for a later version of CorelDRAW, such as CDR 2018 or 2019, to be able to export an AI file that doesn't turn to garbage when opened in Illustrator. In addition to the CDR or AI file they might provide they'll probably have to include a PDF (that they proof for accuracy in Adobe Reader) so you can see how the fills.
• To convert a beta or preview version to a full version, uninstall the beta or preview and then install the current trial version. To qualify for an upgrade license, you must provide a valid serial number for an earlier version of the same Adobe software application as your tryout.

I haven't tested this one yet, but plan do do so right away. Great tip.

True, but you still have to sucker-punch your client into getting that for you. Any hackish solution is generally easier than getting what you need from a client…
That was meant to be a reply to the 'CS5 can save back to Illustrator 3' comment. Whoops.

Yes, I Should Have Said. If The Newer File Uses Features That Aren't Available In CS Then There Will Be Problems.

Illustrator CS5 can save in older formats well below CS4: When saving or doing a Save As for the first time, you can choose Illustrator CS5 (15), CS4 (14), CS3 (13), CS2 (12), CS (11), 10, 9, or earlier.
Note that this is not the case for Adobe InDesign. InDesign CS5 (7) maintains backward compatibility only to CS4 (6), and only when the INDD document is exported in IDML (InDesign Markup). Similarly, InDesign CS4 (6) is backward-compatible with CS3 (5) when exporting to INX (InDesign Interchange).
--Gerrit

Well, the point of this hints, really, is more about using a newer (postscript-EPS format) file and be able to use it with a legacy software, not really about 'how to save a file to a legacy format'...

Convert Ai To Older Version Online

This would have been a good hint if not for the inaccurate CS5-cannot-save-to-CS3 part. If you had instead focused on the more basic need of how to get the CS5 AI file into CS3 when the client cannot or will not export to a legacy version, then this hint would have been much better.

Jeez louise!
The POINT here is to provide useful tips or useful critiques. >*(
There are clients that will email/FTP a file and want the work completed YESTERDAY. You can't always get a downsized file as that file might be from another source/designer and complicate the production.
The Tip works. As long as you have InDesign and can import/place the EPS.
And yes, CS5 can dumb down to legacy versions, however, you may lose features that newer incorporates (transparencies, layers, ...).
Anyway, thanks for the tip...saves some folks I know from plopping down $$$ to upgrade just to open a CS5 illustrator file...

I think you need to reread the 2nd sentence of the comment you are responding to. The tip is of course useful; it just implies false information. As for your comment about saving to legacy versions, you will not lose much going CS5 to CS3, and anything lost will almost certainly also be lost going the PDF route (i.e., you will get a flattened, not very editable version, with either the CS3 or PDF route).

I am still using CS2... obviously everyone on earth is ahead of me which makes it difficult to open ANY EPS vector files sent to me. Same idea as the InDesign option, and I don't know if it'll work for other versions, but I Control-click the file and go to 'Open With', choose my Acrobat Professional application, save out as PDF and open the PDF in Illustrator. Works like a charm...

Regardless of semantics... it worked and saved me from emailing the client (once again) to ask for digital assets.
Thanks for the tips!