r4nchy
The command you're running doesn't actually dictate which version of Flarum you install.
You'll need to run composer create-project flarum/flarum ., then modify composer.json to force flarum/core to 1.3.1. After this, run composer update, then point Flarum at your old DB.
Make sure everything works as expected, then you can upgrade to Flarum 1.4 by updating the requirement in composer.json to ^1.4, and running composer update.