It is now "natively running in 1080p," with textures and draw distances improved for sharper visuals, and there's volumetric fog too. Sadly, mod support isn't so definitive.
While the dev team are "aware of the amazing stuff" the community has slapped together for Sleeping Dogs in the past, support just "isn't possible" for this release.
The "tried to maintain the integrity" of the original, but combat itself has been adjusted with things like the counter window time. "The camera, vehicles and physics have also seen their fair share of love as well and so have the DLCs. "also revealed gameplay has been tweaked, both in the main story and its DLC. Overall they've
Sleeping Dogs: Definitive Edition releases on PC, Xbox One and PS4 October 10th in the UK, 14th in the US.