patentable subject matter. The court ordered the application sent back to the Commissioner for expedited re‑examination with the direction that the claims constitute patentable subject matter. The Commissioner of Patents appealed to the Federal Court of Appeal. At the Federal Court of Appeal, court agreed with much of the judgement of the Federal Court, but found that it was inappropriate for the Federal Court to engage in claims construction absent a "foundation of knowledge about the relevant art". The Federal Court of Appeal remanded the construction of the patent claims back to the Commissioner for expedited re-examination. The Commissioner of Patents issued the patent in December 2011. In March 2013, the Canadian Patent Office issued guidance on revised office practice. On March 8, 2013, the Canadian Patent Office announced changes in patent examination practice based on the ruling in the Amazon.com case. CIPO published new guidelines for determining whether an invention constitutes statutory subject matter based on a purposive construction of the claims. Updated guidance on examination practice for computer-related inventions was also published at the same time. References Canadian patent law Canadian intellectual property law