Are there any best practices for setting headers in PHP to ensure compatibility with different browsers, including older versions like IE 6?

When setting headers in PHP, it is important to consider compatibility with different browsers, including older versions like IE 6. One way to ensure compatibility is to include specific headers that address common issues with older browsers, such as caching and content type declarations. By setting these headers appropriately, you can improve the performance and functionality of your website across a wide range of browsers.

header('Cache-Control: no-cache, must-revalidate');
header('Expires: Sat, 26 Jul 1997 05:00:00 GMT');
header('Content-Type: text/html; charset=utf-8');