Square Enix has confirmed that Year of the Snake will be coming in the first three months of 2013 for Sleeping Dogs, along with some other unreleased DLC.
The DLC includes:
Year of the Snake
Wei Shen's story continues in Year of the Snake as he rejoins the ranks of the Hong Kong Police Department in a series of new missions set immediately after the main game. A vicious end-of-the-world cult is taking root in the back streets of Hong Kong... the Cult of the Snake. Hell-bent on cleansing the city of its evils, they cannot be negotiated with as they pursue a path to their righteous salvation. With an arsenal of weapons, including teargas guns and electroshock pistols, new outfits and abilities, Wei must enter a race against the clock to bring the cultists to justice before Judgment Day.
Wheels of Fury Pack
Drug smuggling is big business for Hong Kong's triad gangs and Wei Shen's longtime friend Dr Tang has created the wheels to give the Sun On Yee the edge over their rivals. A weaponised supercar, the prototype DZS-90 will give Wei Shen enough armour and firepower to take control of business. Seize the streets back from the 18K with a series of upgrades and add-ons available on completion of each mission, building into the ultimate supercar available both in missions and in the open world.
Law Enforcer Pack
No criminal in Hong Kong is safe from justice. The Law Enforcer Pack gives players their most comprehensive access yet to police department gear, including two cop outfits, a new weapon and five police vehicles.
Other DLC mentioned for Sleeping Dogs included content already released including The Movie Masters Pack and The Monkey King Pack.