This is the original message, they sent;
Police certificates for yourself, your spouse and each dependent child over the age of 18
o You, your spouse and your dependent children over the age of 18 must submit an updated police certificate from the country where they are currently residing
o You must submit a police certificate from every country where you and your spouse have resided more than six months if it has not already been submitted; this requirements applies also to your dependent children if they have resided in foreign countries for more than six months after their 18th birthday
o Our website contains useful information on how to obtain foreign police certificates: http://www.cic.gc.ca/english/information/security/index.asp
But on the immigration application package guide on CIC's website, it says;
Police certificates
All applicants must submit police certificates/clearances as part of the application process.
You and all of your family members who are 18 years of age and older and who are not already permanent residents or Canadian citizens will have to provide:
•a valid police certificate, or
•police clearance, or
•record of no information.
These documents are to be provided for each country other than Canada, in which you have lived for six consecutive months or longer since reaching the age of 18.
Here is the link;
http://www.cic.gc.ca/english/information/applications/guides/EG7TOC.asp