nothing needs to be done if you use the online versions. you would access your account as you did previously. for desktop the app would need to be reinstalled and updated. Only 2019-2022 are currently available. no updates or state returns are available for earlier years. if you want earlier years' returns you need to open the app on the old computer for that year and save the return as a PDF. note that the IRS only retains copies of the return for 6 years so returns earlier than 017 are likely no longer available.
warning: if you have the installation files for earlier years, they can be installed but if you can open the file (the lack of a state program if needed may prevent this) you will end up changing it from what was filed. another way to get copies of earlier years is to use a website like https://www.taxprinter.com/ . They're not affiliated with turbotax and while there have been no report of problems no assurances can be given.
