Several of our sites have a fatal error when updating to 5.9.7
Uncaught Error: Class "MetaBox\Block\Register" not found in /nas/content/live/******/wp-content/plugins/meta-box/inc/loader.php:113 Stack trace: #0 /nas/content/live/******/wp-content/plugins/meta-box/meta-box.php(19): RWMB_Loader->init() #1 /nas/content/live/******/wp-settings.php(473): include_once('/nas/content/li...') #2 /nas/content/live/******/wp-config.php(133): require_once('/nas/content/li...') #3 /nas/content/live/******/wp-load.php(50): require_once('/nas/content/li...') #4 /nas/content/live/******/wp-admin/admin-ajax.php(22): require_once('/nas/content/li...') #5 {main} thrown on line 113 in file wp-content/plugins/meta-box/inc/loader.php
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