Legacy projects can be a pain – you have to not just support an old code but add new features. And at some point this may become a nightmare. However, there are many ways to upgrade it without full re-development at one time. One possible solution is to move such projects to the modern Laravel ecosystem as it’s described in this article.
The idea behind of it is to wrap the old code to handle it by Laravel. Once it’ll be done, the old functionality will work as expected, while all new features will be added in Laravel. Additionally the old code can be refactored and moved under Laravel without a downtime or an interruption of the project. This solution will give a smooth transition from old system to the new one.
Also do not forget about tests – unit and integration, static analyzers like PHPStand and code style control with PHPCS. This will help you to catch possible bugs even before run your app.