From the feature page quote:

Plus prevent your databases from being opened with previous versions of FileMaker Pro.

I'm reading a lot into this, but is there anyway to know if this prevention feature would also prevent a hash replaced file from opening.

I guess what I'm lookin for is some assurance that there is some new encryption that would prevent the detection of hashes, if the file was saved via FM11. Has anyone tested these new security features, are they still leaving a .FM7 file vulnerable to existing cracks if it has been saved via FM11 and set to open only with FM11? I'd love to hear that by checking this option a new level of encryption is used, thus making previous cracks unuseable.

The new File Access Protection feature has no relationship to the action of crackers. BTW, the crackers don't "detect" the hashes in the sense of reversing them. They simply tear them out of the file, damaging the file in the process, and then substitute their own hash of a set of credentials known to the cracker.

Steven