請教Immcanada和其他好心人

I am in US now and since I came here I never went back. I have the 無犯罪公證which was issued about 8 years ago before I left China, can I still use it for immigration to Canada? If I need to get updated police clearance, will another 無犯罪公證 do it or I have to really contact the police department in China? Thanks very much in advance.