A paper was published on the Canadian Intellectual Property Office, dating back to 2001. That was a technical paper and went through the various possibilities for accession to Madrid and Singapore. Following that, the Canadian Intellectual Property Office did conduct consultations that were open to all stakeholders and intermediaries in 2005 and again in 2010. Dedicated or targeted consultations were also conducted in the fall of 2013.
On May 29th, 2014. See this statement in context.