Hi Stephane
>I had an old project which is not opening with my current version of creo.
That`s not normal
If you have the full version to save .pkg you can open older versions of the program "ptc Direct Modeling".
But if you have only ""Direct Modeling Express 6.0" or earlier there is only one way.
Unfortunately Pkg and Pk2 are incompatible.
The only way is to save Pkg as .step and load this in Express X.
I'll can do that for you. Have a look in your post.
Again unfortunately, if you have made some drawings in Annotation you will lose them.
All connections between model and drawing are no more present after this transfer.
Best regards 