Compatibility Issues between InDesign CS3 and InDesign CS4

Students using InDesign CS4 should be mindful of these two items:

1. You can not open CS4 document in InDesign CS3. CS4 files must be exported as Indesign CS3 Interchange (INX)
files, then they can be opened by InDesign CS3 or higher, but no lower.

2. If you open InDesign CS3 files in CS4, work on them, then save back down to CS3 the results may be unpredictable. Those features that are not compatible will be lost (older InDesign does not support versions, transitions or any of the new features).