I am user of Poser from its debut so i have lots of files in different Poser versions I am also user of DAZStudio from its debut (payed version of pro) and now i am using it most of time and i import Poser file in DAZ and i use Poser figures, props etc directly fom one of my Poser libraries So can someone from inside Poser 12 development can precise if i can continue to import or use Poser files for this version 12 If yes i will buy If no i don't buy ( i have the same question for Vue infinite)

I am not on the development team but it would be counterproductive if Poser 12 is an entirely different program from its predecessors. It would be safe to assume that every that you used in the past will be available to you in Poser 12.

So, to clarify, you're asking a number of questions here:

i) is it likely I can continue to use older Poser content in Poser 12?

Almost certainly. Backward compatibility is a given with new versions of Poser. Though the exception to that rule is the PoserPython scripts. Some will break with Poser 12, as it will update to the latest Python version. But so far as I know people are already working on fixing key scripts. Other scripts will almost certainly be fixed or replaced-by-better in due course.

ii) will I be able to save content in Poser 12 and then open it in DAZ Studio?

You'll be able to get a free trial version of Poser 12, so you can just try it and test it before you buy.

iii) Will the old Vue Infinite import scenes saved with Poser 12?

That's one of the many varieties of the pre-subscription Vue, I think, which makes it ancient history for E-on. I know that Poser 11.x has no problem moving a Poser scene to either a) the old Vue 2016 R5 (the 'last good' version, avoid R4 because it temporarily bjorked-up Poser scene import) or b) the new subscription-only Vue. However there are said to be Material Room changes in Poser 12, so who knows... that might affect the way Vue handles certain new/advanced forms of texture from Poser? I would imagine that E-On will fix their new Vue for Poser 12, eventually, if a relatively trivial textures import fix is needed. Why wouldn't they? But if they don't, then perhaps it will just become a multi-step process - save the Poser 12 scene, open it in old 'pre phone-home' copy of Poser, save, then open in your old 'pre phone-home' Vue Infinite. But that's the way it rolls, getting older software to talk to newer software. Again, there will be a free trial for Poser 12 to test such things before purchase.

Thanks HartyBart The trial version is the way to test