What are best practices for updating and maintaining PHP-based applications to ensure compatibility with different browsers?

To ensure compatibility with different browsers when updating and maintaining PHP-based applications, it is important to use modern web development practices such as responsive design, CSS resets, and testing across multiple browsers. Additionally, keeping PHP libraries and frameworks up to date can help address any browser compatibility issues that may arise.

// Example of using a CSS reset to ensure consistent styling across browsers
<head>
    <style>
        /* CSS reset */
        body, h1, p {
            margin: 0;
            padding: 0;
        }
    </style>
</head>