Hello,
From what I have read before around here, if your application was already approved and you got ppr, you will get your visa and study permit at the border with no issue. You may get a question about why you’re coming in past the stated date in your file, but I’m pretty sure that if you show them your new acceptance letter you will be fine. What may happen though is that you may need to apply at some point for a study permit extension, that since you’ll be starting a semester later than the length your SP was originally issued for.
If your application is still pending though, IRCC will probably ask you to send them your updated LOA once they start working on your file. In any case, it something that happens a lot and it shouldn’t hinder your application outcome, so don’t overthink it and get stressed by that. The process itself is stressful enough!