PHP 8.4: What’s New — Hands-On Guide

PHP 8.4 focuses on developer ergonomics: property hooks to intercept reads/writes, asymmetric visibility, a spec-compliant HTML5 DOM API, new array_* helpers, and quality-of-life syntax tweaks. Hooks enable computed properties and validation with zero boilerplate.

class Locale {
    public string $lang;
    public string $country {
        set (string $v) {
            $this->country = strtoupper($v);
        }
    }
    public string $code {
        get => "{$this->lang}_{$this->country}";
        set (string $v) {
            [$this->lang, $this->country] = explode('_',$v,2);
        }
    }
}
$l = new Locale();
$l->code = 'uk_ua';

Asymmetric visibility lets you expose a property for reading while restricting writes (public private(set)), cutting down on artificial getters.

class Version { 
    public private(set) string $v = '8.4'; 
} 
$ver = new Version(); 
echo $ver->v; // can read // $ver->v = '9.0'; // error write

Arrays get array_find, array_find_key, array_any, array_all so you can drop hand-rolled loops.

$animal = array_find(['dog','cat','cow'], fn($x)=>str_starts_with($x,'c')); // 'cat'

The brand-new DOM lives under Dom\* and understands HTML5 (querySelector, classList), a huge upgrade over DOMDocument.

$doc = Dom\HTMLDocument::createFromString('Hello');
$node = $doc->querySelector('article');
var_dump($node->classList->contains('featured')); // true

More goodies: method/property access on new without parentheses, a RoundingMode enum with extra modes for round(), the BcMath\Number class, mb_trim/mb_ucfirst, microsecond helpers on DateTime, and driver-specific PDO subclasses (Pdo\Pgsql, etc.).

$result = round(2.5, 0, RoundingMode::AwayFromZero); // 3 var_dump(new PhpVersion()->getVersion()); // без (new ... )

Before upgrading, note that IMAP, OCI8, PDO_OCI, and pspell moved to PECL; implicitly-nullable parameter types are deprecated; and exit() semantics changed in certain contexts—scan the migration guide.

Bottom line: PHP 8.4 reduces ceremony and sharp edges while boosting the DOM and numeric/tooling story. Want to try it today? Spin it up on our VPS or update your app on Shared Hosting; keep safe with S3 storage.