- the current trial running on older versions of my product won't be reset ?
The trials won't be reset, no.
- with older versions, TrialDaysRemaining() will returns the remaining days for current trial, right ?
Well, it depends. If they get the new *.dat file then, no, they'll get 0 days remaining.
- with the new version (with new DAT file), TrialDaysRemaining() should always returns zero ?
Yes.
- if I use a trial extension on new version, TrialDaysRemaining() will return the remaining days for the trial extension ?
Yes.