Upgrading Laravel 5.4 to latest version (5.7)
Better to upgrade 5.5 first an then go with 5.6 and 5.7 because if you see in 5.5 and 5.6 upgrade guide there are some packages also need to upgrade so you better go with the step by step.
For older versions, you can look at
From my point of view, it would help to upgrade step by step. This helps to to see whether your application is already compatible with all changes that need to be made.
If you upgrade to 5.7 directly and face larger problems due to the changes, your quickest option is to downgrade to 5.4 again.
If you upgrade to 5.5 in the first step, you can make your application compatible to 5.5, test it thoroughly, deploy it, and start to test what needs to be done for the upgrade to 5.6.