Modifying a Composer library that is on Packagist is easy! Follow the steps below:

• Fork the library on GitHub (must contain composer.json file)
• Push your library changes to the main branch (You can check which one it is on Packagist, under “Source:” – Example)
• Add an override to your applications composer.json file to use your fork.

Before (Using official Packagist repo)

{
    "require":
    {
        "torophp/torophp": "dev-master"
    }
}

After (Overriding with your own fork)

{
    "repositories":
    [
            {
                "type": "vcs",
                "url": "https://github.com/khromov/ToroPHP"
            }
    ],
    "require":
    {
        "torophp/torophp": "dev-master"
    }
}

Now you can run:

composer update 

Composer should tell you that files have been modified. Answer “Y” to any questions. Congratulations! You are now using your own fork.