PHP 8.1 | White screen after plugin update

Hi there

I guess the following PHP fatal error is connected with the MailPoet plugin – could you please take a look at it?

2022/12/07 09:00:35 [error] 28077#28077: *1576446 FastCGI sent in stderr: "PHP message: PHP Fatal error:  Uncaught Error: Call to undefined function request_filesystem_credentials() in /home/wp/disk/wordpress/wp-admin/includes/class-wp-upgrader-skin.php:140
Stack trace:
#0 /home/wp/disk/wordpress/wp-admin/includes/class-wp-upgrader.php(189): WP_Upgrader_Skin->request_filesystem_credentials()
#1 /home/wp/disk/wordpress/wp-admin/includes/class-language-pack-upgrader.php(206): WP_Upgrader->fs_connect()
#2 /home/wp/disk/wordpress/wp-content/plugins/mailpoet/lib/Config/Localizer.php(53): Language_Pack_Upgrader->bulk_upgrade()
#3 /home/wp/disk/wordpress/wp-content/plugins/mailpoet/lib/Config/Activator.php(87): MailPoet\Config\Localizer->forceInstallLanguagePacks()
#4 /home/wp/disk/wordpress/wp-content/plugins/mailpoet/lib/Config/Activator.php(60): MailPoet\Config\Activator->processActivate()
#5 /home/wp/disk/wordpress/wp-content/plugins/mailpoet/lib/Config/Initializer.php(334): MailPoet\Config\Activator->activate()
#6 /home/wp/disk/wordpress/wp-content/plugins/mailpoet/lib/Con" while reading response header from upstream, client: [...], server: [...], request: "GET /wp-admin/update-core.php HTTP/2.0", upstream: "fastcgi://unix:/var/run/wordpress.php-fpm.sock:", host: "...", referrer: "/wp-admin/update.php?action=update-selected&plugins=gp-premium%2Fgp-premium.php%2Cmailpoet%2Fmailpoet.php&_wpnonce=..."

Thanks a lot,
Michael