I don't understand your point.
What could be illegal about it?
If you mean because it can write or copy dual layer DVDs then why would be illegal? Dual layer DVDs are coming soon. Not all films are released on dual layer DVDs. Goodfellas has to be turned over halfway through but your not worried about your softwares ability to copy single sided discs.
Unless it mentions that it can crack any copy protection then it perfectly legal just like any software that can burn data to single layer DVDs, CDs or your tape recorder (how old does that sound???) at home.
Its just an update to cover a new type of DVD thats all. Anyone currently storing data across more than one DVD will be pleased to be able to use one double layer for every two single layer.
Or have i missed something?