Syntax error when using PHP7.4

[WHITE-developer]

When going to the mail settings page we get the following error:

syntax error, unexpected '|', expecting ';' or '{'
in /var/www/html/vendor/perfectwebteam/craft-mailchimp-transactional/src/mail/MailchimpTransactionalAdapter.php at line 101

    {
        return Craft::$app->getView()->renderTemplate('mailchimp-transactional/settings', [
            'adapter' => $this,
        ]);
    }
 
    /**
     * @inheritdoc
     */
-->    public function defineTransport(): array|Swift_Transport
    {
        return [
            'class' => MailchimpTransactionalTransport::class,
            'constructArgs' => [
                [
                    'class' => Swift_Events_SimpleEventDispatcher::class
                ]
            ],
            'apiKey' => Craft::parseEnv($this->apiKey),

Craft 3.7.33
PHP 7.4

[sanderpotjer]

@WHITE-developer thanks! We just pushed an update that will fix this.