Hi, we have several designers located around the globe, that all need to be able to access & change the same design files, mostly Indesign. They are all using Applemacs, but all have different CS versions, i.e. CS5.5, 5.7 and 220.127.116.11. We already had problems where a 5.7 user couldn't open a file saved by a 5.5 user. If my logic serves me correct, newer versions of software should be able to open older versions' files, but the opposite would not be necessarily true. Or does CS operate differently?
Do you have any advice, please are they doing something wrong?
First off, I'm not aware of any InDesing version numbered 5.7, so you need to double-check what versions everyone is using, and second, you probably should stick to one numbering system. The "CS" versions started with InDesign Version 3.0, so CS is version 3.0.x, CS2 is version 4.0.x, CS3 is version 5.0.x (last patch was 5.0.4), CS4 is version 6.0.x, CS5 is 7.0.x (last patch was 7.0.4), CS5.5 is version 7.5.x (last patch was 7.5.3) and CS6 is version 8.0.x, currently at 8.0.1.
Once you get your version numbering straight I think you'll find that things work as you expect -- newer versions of ID can open older version files, but not vice versa.