What are the best practices for handling special characters, such as umlauts, when processing JSON data in PHP?

Special characters, such as umlauts, can cause issues when processing JSON data in PHP due to encoding differences. To properly handle these characters, it is recommended to use the `json_encode` function with the `JSON_UNESCAPED_UNICODE` flag to ensure that the special characters are not escaped. This will preserve the original UTF-8 encoding of the characters in the JSON output.

$data = ["name" => "Müller"];
$json = json_encode($data, JSON_UNESCAPED_UNICODE);
echo $json;