You will need to download the software for each year: https://turbotax.intuit.ca/tax-software/prior-year-taxes.jsp#2014
Turbotax desktop only goes as far back as 2014 for download.
Make sure to scroll to bottom of screen to Download tax software - this is the desktop version, with forms mode. Prior to 2019 tax year, all other tax years have the latest updates.
You can always ensure that you have the latest updates by going to the Help menu > Check for Updates.
I am looking to update my 2013 and 2014 but when I follow your link, it takes me to a page where I have to pay for the software. Can I not update my existing software?
Unfortunately you can't do that. An error message is returned that says: TurboTax is unable to determine if an update is available. You can download updates from the TurboTax support website at http://www.TurboTax.ca/support
Error Code: TT810
But there is no links for updates on this page?
You can download the previous years' installers at below location:
Please ignore the check for updates errors.