Ok, here's a little trick I figured out today that I had previously been told was "impossible." I opened a file created in InDesign CS4 with InDesign CS. And it looked ok.
InDesign, much like QuarkXpress, only lets you save down one version with the "interchange" (.INX) format. So if you create a document in CS4 and need to open it in CS3 you do "Save As" select the Interchange format and then open that (rather than the .indd file) in CS3.
Ah! But what do you do if you need to open that file in an InDesign version OLDER than the the previous version and you don't have access to the version(s) in between? Most people (including Adobe) will tell you that you're screwed. But you're not! Or at least not totally screwed.
When you save to INX format it creates an XML file which the previous version uses to rebuild the structure of the document it's own way as best it can (assuming it has all the updates to the program and plugins applied). If it encounters any data it doesn't understand (for example, features that were added to the newer version) it will just ignore that stuff and move on. Obviously that means the more features you used that aren't backwards compatible the more screwed up your file will be when it's opened in an earlier version. BUT, if you have a fairly simple layout you may not need to tweak anything.
Since the INX file is just a text file you can easily open it with WordPad or NotePad (on Windows) or Text Editor (on Mac) and you only need to change ONE STINKIN' NUMBER to make this work, and it's in the second line of the file. Let's say I've created a file in InDesign CS4 and used the Interchange format to save it backwards for InDesign CS3. The second line of the INX file will read something like:
?aid style="33" type="document" DOMVersion="6.0" readerVersion="5.0" featureSet="257" product="6.0(578)" ?
The "6.0" then refers to CS4, from which we exported the file. The "5.0" in the "readerVersion=" part means CS3, because we told it to save it for CS3 which will be "reading" the INX file.
To open this file in CS2 without actually having access to CS3
Change: readerVersion="5.0" --> readerVersion="4.0"
To open this file in CS without actually having access to CS2 or CS3
Change: readerVersion="5.0" --> readerVersion="3.0"
That's IT! The INX file I exported from CS4 opened in CS perfectly. Then I immediately just saved it as a different name as an .indd CS compatible file. Granted it was a simple layout and apparently didn't use ANY special features added to the software between CS and CS4. Odds are most files will lose something going backwards in time that far, but the point is to be able to OPEN the file so you don't have to rebuild it from scratch.
