PHP 8.2 End of Life

Implicitly nullable parameters are deprecated (8.4)

A parameter with a type and a default of null, like Type $x = null, now raises a deprecation. Write ?Type $x = null. This is the most common warning after an upgrade to 8.4, and tools like PHP-CS-Fixer fix it automatically.

<?php
function greet(string $name = null)
{
    return 'Hello ' . ($name ?? 'world');
}
echo greet();

Run on PHP 8.2 →Run on PHP 8.4 →

Typed class constants and #[\Override] (8.3)

Class constants can declare a type, and the #[\Override] attribute makes PHP check that a method really overrides a parent method. Both are opt-in, so existing code is unaffected.

<?php
class Base
{
    public const string NAME = 'base';
    public function render(): string { return static::NAME; }
}

class Child extends Base
{
    public const string NAME = 'child';

    #[\Override]
    public function render(): string { return strtoupper(parent::render()); }
}

echo (new Child)->render();

Run on PHP 8.2 →Run on PHP 8.3 →

Extensions removed from core (8.4)

IMAP, OCI8, PDO_OCI and Pspell moved from the PHP source to PECL. If you read mailboxes with imap_open(), install the PECL extension or move to a library such as webklex/php-imap before upgrading.

E_USER_ERROR and other small deprecations (8.4)

Calling trigger_error() with E_USER_ERROR is deprecated (throw an exception instead), as are the E_STRICT constant and a few rarely used functions. Run your test suite with error_reporting(E_ALL) on the new version to catch them.