I just noticed a curious point:
If I look into bridge métadata photos it is mentionned Camera Raw process version 6.7 but I use 7.1. Any explanation? another point If I go directly into photo properties details it is indicated 7.1
The Process Version in terms of an ACR version means that was the first version of ACR where that process version was introduced.
The Camera Raw version in the metadata is the version of ACR actually used to create the metadata.
You should find that the metadata ACR version is at least as high as the PV’s version.
ACR 6.7 can use the ACR 7.0 process is more the way to look at it. The only reason the new PV2012 is supported by the old ACR 6.7 is because LR4 with PV2012 was released a couple months before PS-CS6/ACR7.0 came out, so Adobe released ACR 6.7 as a temporary fix allowing LR4 to integrate with PS-CS5 until PS-CS6 was released.
If you look in some older XMP files, that haven’t been touched by ACR 6.7 or ACR 7.x or LR4, then their Process Version is 5.7 because that is the version of ACR that first supported the new adjustments in LR 2.7 just prior to CS5/ACR 6.x being released. Before ACR 5.7 there is no Process Version designation in the XMP files, because the previous time Adobe changed settings was 2003, 4 years before LR 1.0 was available.