audacity 2 convert to audacity 3 ?

Hi, I have a lot of audacity 2 files and I would like to convert them all to audacity 3. Is their a tool to do this or must I convert them one by one?

Either convert them one by one, or just leave them as Audacity 2 projects until you need to work on them.

Audacity projects should be thought of as an intermediate step, not as an end result. The end result is an audio file (such as a WAV or MP3), whereas the Audacity project is the means to get to that result. Be very careful with old Audacity 2 projects - it’s very easy to accidentally destroy them.