1-Netfile is only available for the previous 5 years, which are 2017 to 2021, through the Canada Revenue Agency (CRA) therefore, 2015, 2016 will have to be sent in by mail.
Please see this Canada Revenue Agency link: File your taxes online: Understand NETFILE.
2-You can use TurboTax software starting in 2015 File past years' taxes.
Where to mail your paper T1 return
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