Attempting to get Laravel 5.6 running on a sandboxed Homestead environment. My local php version is 7.0.20 and Laravel 5.6 requires at least 7.1.3. I can't run "composer require laravel/homestead" because it fails due to the php version. I updated my composer.json to require php version 7.0.* and ran composer update. It is still failing when attempting to require laravel/framework.
Is there an obvious solution that I am missing? Thank in advance for any input.