I'm looking to unlock my old s7. I have the IMEI number
@Mattshaughnessy, Providing you did get the phone from Fido, you can reach out to customer service through any of the available methods listed here. They will provide the unlock code along with the instructions.
As I know, if your phone was bought after Dec 1st, 2017, the unlock code is on the sticker attached to the box.
If you cannot find the unlock code, you can call customer service to get the unlock code.
Here are some FAQs