Chybová hláška po konfiguraci PHP

Klientovi se po konfiguraci PHP na 8.1 objevuje na webu tato hláška:
Warning: The magic method Gallery_Video::__wakeup() must have public visibility in /data/web/virtuals/175296/virtual/www/wp-content/plugins/gallery-video/video-gallery.php on line 86

Nyní se nemůžeme dostat ani do administrace wordpressu, hlásí nám to toto:

Warning: The magic method Gallery_Video::__wakeup() must have public visibility in /data/web/virtuals/175296/virtual/www/wp-content/plugins/gallery-video/video-gallery.php on line 86

Warning: Cannot modify header information – headers already sent by (output started at /data/web/virtuals/175296/virtual/www/wp-content/plugins/gallery-video/video-gallery.php:86) in /data/web/virtuals/175296/virtual/www/wp-includes/pluggable.php on line 1427

Warning: Cannot modify header information – headers already sent by (output started at /data/web/virtuals/175296/virtual/www/wp-content/plugins/gallery-video/video-gallery.php:86) in /data/web/virtuals/175296/virtual/www/wp-includes/pluggable.php on line 1430

Co s tím, prosím?

Děkuji.