Exploring PHP 8.4, its New Features and Benefits for WordPress Websites

PHP 8.4, the latest iteration in the PHP 8 series, will be released on November 21, 2024. It introduces several features and improvements to enhance performance, usability, and developer experience. These updates can significantly benefit WordPress websites, making them faster, more efficient, and easier to maintain. Let’s explore the new features of PHP 8.4 and how they can be leveraged in a WordPress environment.

Key Features of PHP 8.4

New Rounding Modes for round()

PHP 8.4 adds four new rounding modes to the round() function: PHP_ROUND_CEILING, PHP_ROUND_FLOOR, PHP_ROUND_AWAY_FROM_ZERO, and PHP_ROUND_TOWARD_ZERO. These modes provide more control over numerical data manipulation, which can be particularly useful for WordPress plugins dealing with financial calculations or any applications requiring precise rounding operations.

Intuitive JIT Disabling

Just-In-Time (JIT) compilation, introduced in PHP 8.0, boosts performance by compiling PHP code to machine code at runtime. However, disabling JIT previously required setting the opcache.jit_buffer_size to 0, which was not intuitive. PHP 8.4 introduces a new directive, opcache.jit=disable, simplifying this process. This change can help WordPress developers manage server resources more effectively, especially when dealing with various hosting environments .

New JIT Implementation

PHP 8.4 features a smarter JIT implementation based on the Intermediate Representation (IR) framework, enhancing performance and efficiency. Although not directly visible to users, this improvement ensures that WordPress sites run faster and more efficiently, particularly under heavy load.

Parsing Huge XMLs

With the introduction of the XML_OPTION_PARSE_HUGE option, PHP 8.4 allows the parsing of large XML files without memory issues. WordPress sites relying on large XML imports, such as bulk content uploads or integrations with external data sources, will benefit from this feature.

Parsing Huge XML Files in PHP 8.4 Example

Creating the XML Parser: First, create the XML parser using xml_parser_create().

Setting the Huge Parsing Option: Use xml_parser_set_option() to set the XML_OPTION_PARSE_HUGE option to true.

Defining Element Handlers: Define the XML parser’s start and end element handlers.

Parsing the XML Data: Use xml_parse() to parse the XML data.

// Define start and end element handlers
function startElement($parser, $name, $attrs) {
    echo "Start element: $name\n";

function endElement($parser, $name) {
    echo "End element: $name\n";

// Create the XML parser
$parser = xml_parser_create();

// Set the XML_OPTION_PARSE_HUGE option to true
xml_parser_set_option($parser, XML_OPTION_PARSE_HUGE, true);

// Set the element handlers
xml_set_element_handler($parser, "startElement", "endElement");

// Define the large XML data (for demonstration, using a simple large string)
$largeXmlData = <<<XML
    <item>Item 1</item>
    <item>Item 2</item>
    <item>Item 3</item>
    <!-- Add more items to simulate a large XML file -->

// Parse the large XML data
if (!xml_parse($parser, $largeXmlData, true)) {
        "XML error: %s at line %d",

// Free the XML parser

Multibyte String Functions

PHP 8.4 introduces multibyte equivalents for the trim(), ucfirst(), and lcfirst() functions, namely mb_trim(), mb_ucfirst(), and mb_lcfirst(). These functions are essential for WordPress websites with multilingual content, ensuring proper string manipulation across various languages.

Using Multibyte String Functions in PHP 8.4 Example

Multibyte trim() Function (mb_trim): This function removes whitespace (or other specified characters) from the beginning and end of a multibyte string.

Multibyte ucfirst() Function (mb_ucfirst): This function capitalises the first character of a multibyte string.

Multibyte lcfirst() Function (mb_lcfirst): This function converts the first character of a multibyte string to lowercase.

// Example multibyte strings
$mbString = " こんにちは、世界! "; // Japanese for "Hello, World!"
$mbStringUpper = "Γειά σου Κόσμε!"; // Greek for "Hello, World!"
$mbStringLower = "Привет, мир!"; // Russian for "Hello, World!"

// Multibyte trim function (mb_trim)
$trimmedString = mb_trim($mbString);
echo "Original String: '$mbString'\n";
echo "Trimmed String: '$trimmedString'\n\n";

// Multibyte ucfirst function (mb_ucfirst)
$ucfirstString = mb_ucfirst($mbStringLower, 'UTF-8');
echo "Original String: '$mbStringLower'\n";
echo "Uppercase First Character: '$ucfirstString'\n\n";

// Multibyte lcfirst function (mb_lcfirst)
$lcfirstString = mb_lcfirst($mbStringUpper, 'UTF-8');
echo "Original String: '$mbStringUpper'\n";
echo "Lowercase First Character: '$lcfirstString'\n\n";

// Function definitions for PHP 8.4

if (!function_exists('mb_trim')) {
    function mb_trim(string $string, string $characters = " \f\n\r\t\v\x00\u{00A0}\u{1680}\u{2000}\u{2001}\u{2002}\u{2003}\u{2004}\u{2005}\u{2006}\u{2007}\u{2008}\u{2009}\u{200A}\u{2028}\u{2029}\u{202F}\u{205F}\u{3000}\u{0085}\u{180E}"): string {
        return mb_ereg_replace("^[$characters]+|[$characters]+$", '', $string);

if (!function_exists('mb_ucfirst')) {
    function mb_ucfirst(string $string, ?string $encoding = null): string {
        if ($encoding === null) {
            $encoding = mb_internal_encoding();
        $firstChar = mb_substr($string, 0, 1, $encoding);
        $rest = mb_substr($string, 1, null, $encoding);
        return mb_strtoupper($firstChar, $encoding) . $rest;

if (!function_exists('mb_lcfirst')) {
    function mb_lcfirst(string $string, ?string $encoding = null): string {
        if ($encoding === null) {
            $encoding = mb_internal_encoding();
        $firstChar = mb_substr($string, 0, 1, $encoding);
        $rest = mb_substr($string, 1, null, $encoding);
        return mb_strtolower($firstChar, $encoding) . $rest;

Creating and Parsing an HTML5 Document: We create an instance of DOM\HTMLDocument and parse an HTML5 string.

Manipulating the Document: We manipulate the document by adding a new element to the parsed HTML5 content.

Serialising the Document: Finally, we serialise the modified HTML5 document back to a string.

// Ensure this script is run in PHP 8.4 environment
if (version_compare(PHP_VERSION, '8.4', '<')) {
    die("This script requires PHP 8.4 or higher.");

// HTML5 content to be parsed
$htmlContent = <<<HTML
<!DOCTYPE html>
<html lang="en">
    <meta charset="UTF-8">
    <title>Sample HTML5 Document</title>
    <h1>Hello, World!</h1>
    <p>This is a sample HTML5 document.</p>

// Create an instance of DOM\HTMLDocument
$doc = \DOM\HTMLDocument::createFromString($htmlContent);

// Verify parsing
echo "Original Document:\n";
echo $doc->saveHTML();
echo "\n\n";

// Manipulate the document: Adding a new paragraph
$newParagraph = $doc->createElement('p', 'This is a new paragraph added to the HTML5 document.');

// Serialize the modified document back to a string
$serializedContent = $doc->saveHTML();

// Display the modified document
echo "Modified Document:\n";
echo $serializedContent;

Grapheme Cluster Support in str_split

PHP 8.4 introduces grapheme_str_split(), which returns an array of grapheme clusters. This function is vital for accurately splitting strings containing complex characters, such as emojis or combined characters, ensuring that WordPress content displays correctly regardless of character complexity.

Using grapheme_str_split() in PHP 8.4 Example

Splitting a String with Emojis: We use grapheme_str_split() to split a string containing emojis into individual grapheme clusters.

Splitting a String with Combined Characters: We demonstrate how grapheme_str_split() accurately handles combined characters.

// Ensure this script is run in PHP 8.4 environment
if (version_compare(PHP_VERSION, '8.4', '<')) {
    die("This script requires PHP 8.4 or higher.");

// Example string containing emojis and combined characters
$emojiString = "Hello 👋🌍!";
$combinedCharString = "áéíóú"; // Characters with combining accents

// Function to display grapheme clusters
function displayGraphemeClusters($string) {
    $graphemes = grapheme_str_split($string);
    foreach ($graphemes as $index => $grapheme) {
        echo "Grapheme $index: $grapheme\n";
    echo "\n";

// Splitting the string containing emojis
echo "Splitting string with emojis:\n";

// Splitting the string with combined characters
echo "Splitting string with combined characters:\n";

New HTTP Response Header Functions

The new http_get_last_response_header() and http_clear_last_response_headers() functions provide a more straightforward way to handle HTTP response headers. These functions simplify managing HTTP headers, which is crucial for developing WordPress plugins that interact with external APIs.

Using http_get_last_response_header() and http_clear_last_response_headers() in PHP 8.4 Example

Making an HTTP Request: We use file_get_contents() to make an HTTP request.

Retrieving HTTP Response Headers: We use http_get_last_response_header() to retrieve the headers of the last HTTP response.

Clearing HTTP Response Headers: We use http_clear_last_response_headers() to clear the stored HTTP response headers.

// Ensure this script is run in PHP 8.4 environment
if (version_compare(PHP_VERSION, '8.4', '<')) {
    die("This script requires PHP 8.4 or higher.");

// URL to make the HTTP request to
$url = "https://jsonplaceholder.typicode.com/posts/1";

// Making an HTTP request using file_get_contents
$response = file_get_contents($url);

// Retrieving the last response headers
$responseHeaders = http_get_last_response_header();

echo "HTTP Response Headers:\n";

// Clearing the last response headers

// Attempting to retrieve the headers again to ensure they are cleared
$clearedHeaders = http_get_last_response_header();

echo "\nAfter clearing, HTTP Response Headers:\n";

Property Hooks

One of the most significant updates in PHP 8.4 is the introduction of property hooks, allowing developers to define, get and set hooks for class properties. This feature reduces the need for boilerplate code and enhances code readability and maintainability. For WordPress developers, this means cleaner, more efficient code for custom themes and plugins.

Property Hooks Example

In this example, we create a class that manages book details, including authors. We use property hooks to dynamically generate a list of author names and manage the main author property.

// Ensure this script is run in PHP 8.4 environment
if (version_compare(PHP_VERSION, '8.4', '<')) {
    die("This script requires PHP 8.4 or higher.");

class Author {
    public function __construct(public string $name) {}

class BookViewModel {
    private array $authors = [];
    private ?Author $mainAuthor = null;

    public function __construct(array $authors) {
        $this->authors = $authors;

    public string $credits {
        get {
            return implode(', ', array_map(fn($author) => $author->name, $this->authors));

    public Author $mainAuthor {
        set(Author $mainAuthor) {
            $this->mainAuthor = $mainAuthor;
            if (!in_array($mainAuthor, $this->authors, true)) {
                $this->authors[] = $mainAuthor;
        get => $this->mainAuthor;

// Example usage
$authors = [new Author("Author One"), new Author("Author Two")];
$book = new BookViewModel($authors);

// Display initial credits
echo "Credits: " . $book->credits . "\n";

// Set a new main author
$book->mainAuthor = new Author("Author Three");

// Display updated credits
echo "Updated Credits: " . $book->credits . "\n";

// Display main author
echo "Main Author: " . $book->mainAuthor->name . "\n";

Chaining Methods on New Without Parentheses

PHP 8.4 allows chaining methods on new without additional parentheses. This feature streamlines the code, making it more concise and readable. WordPress developers will appreciate this improvement when writing cleaner and more maintainable code.

Chaining Methods on New Without Parentheses in PHP 8.4 Example

Creating a Class with Chainable Methods: We define a class with methods that return the instance ($this) to allow method chaining.

Using Method Chaining Without Additional Parentheses: We create an instance of the class and chain methods directly on the new keyword.

// Ensure this script is run in PHP 8.4 environment
if (version_compare(PHP_VERSION, '8.4', '<')) {
    die("This script requires PHP 8.4 or higher.");

class FluentBuilder {
    private string $result = '';

    public function add(string $text): self {
        $this->result .= $text;
        return $this;

    public function addLine(string $text): self {
        $this->result .= $text . PHP_EOL;
        return $this;

    public function getResult(): string {
        return $this->result;

// Example usage: Chaining methods on new without additional parentheses
$output = new FluentBuilder
    ->add(" ")
    ->addLine("This is a new feature in PHP 8.4.");

echo $output->getResult();

Benefits for WordPress Websites

Enhanced Performance

The new JIT implementation and improved handling of large XML files contribute to faster execution times and better resource management. These enhancements ensure that WordPress websites remain responsive and can efficiently handle increased traffic and data loads.

Better Multilingual Support

With the addition of multibyte string functions, WordPress websites can better support multilingual content, providing a seamless experience for users across different languages and regions .

Modern HTML5 Handling

The ability to parse and serialise HTML5 documents aligns WordPress with modern web standards, ensuring that themes and plugins can leverage the latest HTML5 features and improvements.

Simplified Development

Property hooks and the ability to chain methods on new without parentheses reduce boilerplate code, making development faster and more efficient. This allows WordPress developers to focus more on creating innovative features and less on repetitive coding tasks .

Improved API Interactions

The new HTTP response header functions make it easier to manage API interactions, which is crucial for WordPress plugins that rely on external services. This results in more reliable and maintainable integrations.

PHP 8.4 brings many new features and improvements that significantly benefit WordPress websites. From enhanced performance and multilingual support to modern HTML5 handling and simplified development, these updates provide WordPress developers with the tools they need to create faster, more efficient, and user-friendly websites.


PHP 8.4 New Features Overview

PHP 8.4 Release Date and Updates

In-Depth Look at PHP 8.4 Improvements

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