No matter where in the world the ownership of a Canadian patent is in dispute, a contract of assignment is void if not registered at the Canadian Intellectual Property Office (“CIPO”), according to the Federal Court (“FC”), pursuant to s. 51 of the Patent Act.
In this case, the FC declined to decide whether to replace John W. Baker (“Baker”) as the owner of Canadian Patent No. 2,222,058, with SALT Canada Inc. (“Salt”), citing lack of jurisdiction over what is primarily a contractual dispute.  Although it had already decided the case on those grounds, the FC went on to comment that, in cases where conflict of laws principles apply (this dispute occurred between multiple U.S. parties), since the statutory rights in a patent are governed by the laws of the jurisdiction in which the patent was granted, no assignment or transfer of the patent can take place except in accordance with the laws of that jurisdiction. 
Specifically with reference to Canada, and since the dispute involved numerous assignments between numerous parties, some of which were never registered at CIPO, the FC commented that nothing in the assignment agreements could supersede the operation of section 51 of the Patent Act,  which requires that any assignment is void against a subsequent assignee unless it is registered at CIPO.