It is becoming increasingly likely that you will need to have a smartphone in order to gain entry into the event.
eTickets are still popular and can be presented as printed-out tickets, for this ticket type a smartphone is not required.
eTransfer tickets are gaining popularity. These tickets are transferred to you via a third-party app chosen by the venue, team, or performer. You will have to accept the tickets using a smartphone. On the day of the event, you MUST show your tickets within the third-party app on a smartphone at the venue in order to enter.
Mobile QR tickets are occasionally offered. These will be sent to you by more conventional means but an eTransfer MUST be shown on a smartphone at the venue in order to enter.