I've personally uploaded TurboTax .tax files to ProSeries. Proseries converts the .taxfile to a Proseries file. However, TurboTax won't be able to convert the Proseries tax file back to a TurboTax .tax file so if your CPA changes anything, you'll have to manually make the change in TurboTax.
- You can upgrade to a higher version but you can't downgrade to a lower version.
As for Lacerte or ProConnect Tax Online, you can give your CPA the .tax2018 tax file and see if he is able to use it with his software.
Related information:
