The last day you can use the old-fashioned paper Transit tickets is on October 31st. Details are here. Originally, the end date for paper tickets was May 31st, but the deadline was pushed back because of COVID-19.
If you have the old paper Transit tickets, you can either use them, or you can take them to the Guelph Transit office on Watson Road, or ServiceGuelph at City Hall where you can convert the old paper tickets into electronic tickets on your brand new OnYourWay card.
More information about the OnYourWay card can be found here.