I’ve recently participated in a number of online discussions concerning backward compatibility in InDesign. It seems to be a popular topic! In response to demand for clarification on the subject I’ve written this article.
Opening Documents from Previous Versions in the Current Version
InDesign has always been able to open documents created in any previous version and convert them to the current version. In addition, ever since CS2 InDesign has been able to open and convert PageMaker files back to PM6. This means that if you have old InDesign or even PageMaker files, you should be able to open them (just as you would open any other file) in newer versions of InDesign without any difficulties.
The conversion occurs automatically when opening. Sometimes minor changes will occur in the file when converting from previous versions, so it’s always a good idea to carefully examine the document after opening it. If the document has become corrupted then InDesign may not be able to convert it.
Inability to Open Newer-version Files in Older Versions of InDesign
InDesign is still relatively young. Each new version contains many new features, so it’s no surprise that document file formats change with each version. For this reason, files created by a newer version of InDesign cannot be directly opened in older versions of the software.
Adobe has traditionally supported the current version and one version back for all of its software. Once software is two or more versions old support for it is officially withdrawn.
In agreement with their support policy, Adobe has given InDesign the capability to export a special type of file that can be opened in the immediately previous version.
Save “One Version Back” with the IDX / IDML File Formats
InDesign CS through CS4 offered the InDesign Interchange Format, with the .idx file exertion. CS4 also introduced the InDesign Markup Language file format, with the extension of .idml, which has since replaced the older IDX format. IDX and IDML are essentially the same thing, though: special XML documents that retain ALL formatting required for the document. They can be opened in the same version from which they were created, as well as one version back. You create an IDX/IDML file via the File: Export menu.
Hypothetical Scenario: From CS5.5 to CS2
So what would it take to open a file created in InDesign CS5.5 in CS2? Unfortunately, a lot of work. Each version of InDesign can only export to the version immediately previous to it. So, hypothetically, to solve this scenario you would have to:
- Open the file in CS5.5 and export it as IDML.
- Open the resulting IDML file in CS4 and export it as IDX.
- Open the resulting IDX file in CS3 and export it as IDX.
- FINALLY open the resulting IDX file in CS2.
Obviously this is not something you want to do on a regular basis! In fact, most of us couldn’t do it even if we wanted to without finding and installing older versions of the software. Even if you did go through this laborious process, functionality may be lost from the document, and changes may occur to the content. Furthermore, it’s not how the IDML/IDX files were designed to be used. The purpose of IDX/IDML is extend support to users who have allowed their software to get slightly behind Adobe’s the release cycle.
The true solution to this scenario is simple: UPGRADE. It’s a fact of life in the digital age. Never allow your Adobe software to get 2 or more versions old. If you do, don’t count on being able to collaborate with someone using the current version.
From CS5.5 to CS5?
Apparently there is significant difference in the file format between CS5.5 and CS5, because CS5.5 users must export their files as IDML in order for CS5 users to open them. A CS5.5 IDML file can also be opened in CS4, according to my own testing that I did while researching and writing this post.
Using IDX/IDML to Fix Corrupted Documents
See my post about how IDX/IDML can help fix corrupted documents.