How can PHP developers efficiently handle special characters like uppercase umlauts in string manipulation tasks?

When handling special characters like uppercase umlauts in string manipulation tasks in PHP, developers can use the mb_strtoupper function along with the mb_internal_encoding function to properly handle multibyte characters. This ensures that characters like uppercase umlauts are converted correctly without causing encoding issues.

// Set internal encoding to UTF-8
mb_internal_encoding("UTF-8");

// Convert string to uppercase with proper handling of multibyte characters
$uppercaseString = mb_strtoupper($inputString);

// Output the uppercase string
echo $uppercaseString;