How do i sign out of 2017 software?

I purchased TurboTax 2017 last year. Can i still use it for 2018?

Getting started

You can still create new 2017 returns with TurboTax CD/Download, but to create a 2018 return, you’ll need to but the 2018 edition. https://turbotax.intuit.ca/personal-tax-software/download-tax-software.jsp