When does Due South return?

Due South is a Canadian crime comedy-drama television series. The series starred Paul Gross, David Marciano, Gordon Pinsent, Beau Starr, Catherine Bruhier, Camilla Scott, Ramona Milano, and Callum Keith Rennie. The show follows the adventures of Royal Canadian Mounted Police (RCMP) Constable Benton Fraser, who first came to Chicago on the trail of the killers of his father, and has remained attached as liaison with the Canadian Consulate.
The premise of the series centres on the exploits of Constable Benton Fraser, an officer in the Royal Canadian Mounted Police. Fraser travels south to Chicago to solve the murder of his father, Sergeant Robert Fraser. During his time in Chicago, Fraser works alongside Detective Raymond Vecchio. Fraser is accompanied by a deaf lip-reading half-wolf named Diefenbaker.