Help for opening comsol4.3

Hello comsolers,

I have a project which is created by Comsol4.3a or 4.3b (I don't know exactly) and I have comsol4.3.
As far as I know comsol4.3 can not open the projects that are created in newer version.

Could somebody help me just changing the version of my comsol project to comsol3.5a, please?
Then I think I will be able to open it by myself.

I need to work with this project, so I will appreciated and be thankful who will help me for this procedure.

Thanks in advance again for your help,
Sepideh