As far as I know PSD hasn't had a "reset", but only incremental features, and compatibility has been good, so I'd expect that not much has changed. Only user perspective though, I haven't looked at the format itself.
Since compatibility is quite important in this case, I don't really expect big changes though. Adobe has a working code base and documentation for it, so there likely is no incentive to risk change.
Since compatibility is quite important in this case, I don't really expect big changes though. Adobe has a working code base and documentation for it, so there likely is no incentive to risk change.