???-Best way to upgrade a Lumen 5.1 project to Lumen 7.0

I have a big project that has been developed using Lumen 5.1 and that includes several custom vendor packages. What I want is to upgrade the current Lumen 5.1 project into Lumen 7.0. There are 2 ways to reach the 7.0 version that is recommended by developers.

1. Upgrade it to Lumen 5.2 from 5.1 and then, Upgrade it to Lumen 5.3 from 5.2 and then, .... Finally, Upgrade it to Lumen 7.0 from 6.0.

2. Upgrade it to Lumen 7.0 from 5.1

And some people say that the best way is to change the current codebase by upgrading composer.json and fix errors/exceptions. And the other people say that the best way is to start from an empty Lumen 7.0 framework and copy/paste every file, folders.

If you have experience in such work, please kindly give me some advice. Best regards.