The downloads for 2017 & 2018 still work (as of March 4th 2025) and these are the last versions. You can download them and run the installer to update them.
2017: https://intuitglobal.intuit.com/downloads/CanadaTax/2017/dls/TurboTax2017_Build9008.exe
2018: https://intuitglobal.intuit.com/downloads/CanadaTax/2018/dls/TurboTax_2018.exe
The link I have for 2016 no longer works, and the old update servers are gone.
