No, your old Sim will just work. Telus, Bell and Rogers all have (sub 6 Ghz) coverage in major cities and aren't charging extra for it at this time (it sounded like they all planned to start charging extra for it after a trial period, but they all have since reversed course on that). If you are with a national flanker brand (Koodo, Virgin or Fido) 5G coverage will probably come much later. Not sure of the status of other regional carriers (SaskTel or Videotron).