What are the best practices for updating PHP code to ensure compatibility with newer versions?

When updating PHP code to ensure compatibility with newer versions, it is important to review deprecated functions and features, use the latest PHP syntax and best practices, and test the code thoroughly on the new PHP version. Additionally, utilizing tools like PHP Compatibility Checker can help identify potential issues before updating.

// Example of updating code to ensure compatibility with newer PHP versions
// Before updating:
$old_array_syntax = array();

// After updating:
$new_array_syntax = [];