What is the test for a variation of an order under s. 17 of the Divorce Act?

The order in this matter that the Applicant seeks to vary was made in default of appearance on August 20, 2009, and provided for child and spousal support retroactive to November 13, 2008. For there to be a variation of that order under s. 17 of the Divorce Act, the court must find there to be a change in circumstances “since the making of the order” in question. I cannot go behind the order or examine circumstances which arose prior to the making of the order: see Gray v. Rizzi, 2016 ONCA 152 (CanLII). I do not know the basis upon which Bielby J. made his order, or, for that matter, what facts he relied upon in doing that, which is necessary before I can establish whether a material change has taken place since his August 20, 2009 order. To that end, I have requested the original divorce file from Brampton, where the Bielby J. order was made. This will allow me to review both the original basis upon which that order was made as well as to examine the issue of whether the Applicant received notice of the divorce proceedings.