Difference between AECOsim SS4 and SS5

Hello,

This is probably a stupid question.

I was under the impression that SS4 and SS5 were just different releases of the same program,

and that data files and seed files were interchangable.

I have now been asked by one of our systems people which version we want to use as they will have to

prepare seed files specifically for that release. Are they correct or have they been misinformed ?

If there are major differences, can somebody point me to a link where I can see the main ones summarised ?

Thanks.

Fraser