Will my old unemployment benefits rules still apply if my claim started before the changes in 2017?

Based on the facts you provided, your benefit period began in May 2017. This date is important because it falls before the legislative changes that took effect on July 9, 2017. Under the Employment Insurance Act, there are specific protections for people whose claims were already active before the law changed. Specifically, the law states that "the following provisions... as those provisions read immediately before July 9, 2017, continue to apply in respect of a claimant... whose benefit period... began before that day and has not ended before that day" [cite:ca-ei-act-sec225]. This means that if your benefit period started in May 2017 and has not yet finished, you are not automatically moved to the new system for everything. For your specific situation regarding your long tenure at the factory, the law explicitly protects your status. The Act specifies that the "definition long-tenured worker in subsection 2(1)" [cite:ca-ei-act-sec225] continues to apply to you. A 'long-tenured worker' is a legal term used to describe someone who has worked for a long time, which seems to match your fifteen-year history. Because the law protects this specific definition, the government should be using the old rules to calculate your benefits based on your long history, rather than the new, stricter rules they mentioned in your notice. While the notice you received says rules might have changed, the law provides these 'transitional' protections to ensure people like you aren't unfairly penalized by new legislation that was passed after your claim was already underway [cite:ca-ei-act-sec225]. Please note that federal laws govern employment insurance, but state, provincial, or local laws may add further rules regarding employment rights.