Starting Version 13.0.0, UTVideo introduced ULH0 and ULHY2. The idea is, when you have HD sources (blu-rays), to use these instead of the ULY0 and ULY2 versions, so that the NLE knows that it should use the Rec.709 colormatrix instead of the Rec.601 colormatrix when doing the conversion.
In this way, you won't have to do colormatrix corrections or colorspace conversions on your own and can in fact just feed your NLE with HD lossless AVI with no worries about the colormatrix fidelity. For SD footage (DVDs) you should still stick to ULY0. For downloaded footage, Lord knows what you could have on your hands and the choice depends on who encoded what source... which might make things no better than a coin toss in some cases (please just buy DVDs and Blu-rays and use those as a source whenever possible).
If version 10.2.0 or older is installed, you have to uninstall that version before you install this version. For more information, see readme.
Just check which version you have and uninstall first before installing the newer one, just to be safe.