Laravel: Update from 5.2.12 to 5.2.31

I have a Laravel 5.2.12 project (website), it's a big project and it's almost finished... Is there any simple way to update the Laravel from 5.2.12 to 5.2.31 without affecting the project (without affecting what was already done)? How can I do this?

So, the question is how to update the version of Laravel on existing project from 5.2.12 to 5.2.31?

via Chebli Mohamed