Fatal error version 5.9.32

Updating to metabox 5.9.3 gave the following warning:

When seeking help with this issue, you may be asked for some of the following information:

WordPress version 6.4.3

Active theme: MH Magazine Child Theme (version 1.0.0) Current plugin: Meta Box (version 5.9.3) PHP version 8.3.2

Error Details

=============

An error of type E_ERROR was caused in line 289 of the file /mnt/web411/c1/77/59783577/htdocs/WordPress_03/wp-content/plugins/meta-box/inc/functions.php. Error message: Uncaught Error: Class "RWMB_Helpers_String" not found in /mnt/web411/c1/77/59783577/htdocs/WordPress_03/wp-content/plugins/meta-box/inc/functions.php:289

Stack trace:

#0 /mnt/web411/c1/77/59783577/htdocs/WordPress_03/wp-content/plugins/meta-box/inc/core.php(26): rwmb_get_registry('meta_box')

#1 /mnt/web411/c1/77/59783577/htdocs/WordPress_03/wp-includes/class-wp-hook.php(324): RWMB_Core->register_meta_boxes('')

#2 /mnt/web411/c1/77/59783577/htdocs/WordPress_03/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters(NULL, Array)

#3 /mnt/web411/c1/77/59783577/htdocs/WordPress_03/wp-includes/plugin.php(517): WP_Hook->do_action(Array)

#4 /mnt/web411/c1/77/59783577/htdocs/WordPress_03/wp-settings.php(643): do_action('init')

#5 /mnt/web411/c1/77/59783577/htdocs/WordPress_03/wp-config.php(82): require_once('/mnt/web411/c1/...')

#6 /mnt/web411/c1/77/59783577/htdocs/WordPress_03/wp-load.php(50): require_once('/mnt/web411/c1/...')

#7 /mnt/web411/c1/77/59783577/htdocs/WordPress_03/wp-admin/admin-ajax.php(22): require_once('/mnt/web411/c1/...')

#8 {main}

? thrown
When seeking help with this issue, you may be asked for some of the following information:

WordPress version 6.4.3

Active theme: MH Magazine Child Theme (version 1.0.0) Current plugin: Meta Box (version 5.9.3) PHP version 8.3.2

I’ve moved back tp 5.9.2 for the time being

The page I need help with: [log in to see the link]