Utu is a plugin used to differentiate the transients of a sound from the Sustain that comes after it. The plugin allows you to then edit these parts separately in terms of shelving EQs and volume, which in the case of the Attack control, allows you to really bring out the smack from your sound, or to remove it pretty much entirely, leaving only the sustain of your instruments. There is a Time control to allow you to control the lenght of the transient tails, which allows you to control what the other controls affect more precisely. A Wet/Dry blend and an Output trim exist to let you blend the effect back into the original audio just as you want it. Buttons also exist to add Vastaus style Smoothing separately to both the Attack and Sustain sections.
Version numbers might be different for platforms, but be assured that the sound is the same :)