V1.7.1 to current v3 upgrade

Hi all,  I've looked and I haven't see any solid info on upgrading multiple versions.

Essentially, I have a project that was originally built on CI 1.7. I'm looking to bring it up to CI 3.1.x.

So, my question is, Do I need to do each upgrade step, Major versions (1 to 2 then 2 to 3), or can I jump straight to v3?

Thanks for any input.