You need to get out more.

PDK is Porsche speak for a dual clutch transmission that of course has an automatic shifting mode very much like that of the old Tip it replaced, but has a manual shift mode (as did the Tip IIRC).

Anyhow, even in manual mode the PDK (controller) prevents the driver from downshifting if in doing so would cause the engine to exceed red line.

Up shifts take place when the driver wants (though there may be a restriction if in doing so would result in the engine revs dropping too low) and this can be at just under the red line treshold. There is even a special manual mode (or it is part of the regular manual mode) in which if the driver does not up shift the revs can reach just under the red line threshold and remain there as long as the driver wants.

Sincerely,

Macster.