version 4.0.0 crash

I upgraded to the new 4.0.0 on php8.1,… and the web crashed… here the detail of the error:

Detalles del error
==================
Se ha producido un error del tipo E_ERROR en la línea 59 del archivo /homepages/1/xxxxxx/htdocs/wordpress/wp-content/plugins/backwpup/vendor/composer/autoload_real.php. Mensaje de error: Uncaught Error: Failed opening required '/homepages/1/xxx/htdocs/wordpress/wp-content/plugins/backwpup/vendor/composer/../amphp/amp/lib/functions.php' (include_path='/homepages/1/xxx/htdocs/wordpress/wp-content/plugins/backwpup/vendor/pear/pear_exception:/homepages/1/xxxxxxxxx/htdocs/wordpress/wp-content/plugins/backwpup/vendor/pear/console_getopt:/homepages/1/xxxxxxxxx/htdocs/wordpress/wp-content/plugins/backwpup/vendor/pear/pear-core-minimal/src:/homepages/1/xxxx/htdocs/wordpress/wp-content/plugins/backwpup/vendor/pear/archive_tar:.:/usr/lib/php8.0') in /homepages/1/xxxxxx/htdocs/wordpress/wp-content/plugins/backwpup/vendor/composer/autoload_real.php:59
Stack trace:
#0 /homepages/1/xxxxxx/htdocs/wordpress/wp-content/plugins/backwpup/vendor/composer/autoload_real.php(42): composerRequire7170161b0cd9ba80095ec7ad7790c1cc('e8aa6e4b5a1db2f...', '/homepages/1/d4...')
#1 /homepages/1/xxxxx/htdocs/wordpress/wp-content/plugins/backwpup/vendor/autoload.php(25): ComposerAutoloaderInit7170161b0cd9ba80095ec7ad7790c1cc::getLoader()
#2 /homepages/1/xxxxx/htdocs/wordpress/wp-content/plugins/backwpup/backwpup.php(60): require_once('/homepages/1/d4...')
#3 /homepages/1/xxx/htdocs/wordpress/wp-content/plugins/backwpup/backwpup.php(176): BackWPup->__construct()
#4 /homepages/1/xxx/htdocs/wordpress/wp-includes/class-wp-hook.php(308): BackWPup::get_instance('')
#5 /homepages/1/xxxxxxxxx/htdocs/wordpress/wp-includes/class-wp-hook.php(332): WP_Hook->apply_filters(NULL, Array)
#6 /homepages/1/xxxxxxxxx/htdocs/wordpress/wp-includes/plugin.php(517): WP_Hook->do_action(Array)
#7 /homepages/1/xxxxxxxxx/htdocs/wordpress/wp-settings.php(480): do_action('plugins_loaded')
#8 /homepages/1/xxxxxxxxx/htdocs/wordpress/wp-config.php(67): require_once('/homepages/1/d4...')
#9 /homepages/1/xxxxxxxxx/htdocs/wordpress/wp-load.php(50): require_once('/homepages/1/d4...')
#10 /homepages/1/xxxxxxxxx/htdocs/wordpress/wp-admin/admin.php(34): require_once('/homepages/1/d4...')
#11 /homepages/1/xxxxxxxxx/htdocs/wordpress/wp-admin/plugins.php(10): require_once('/homepages/1/d4...')
#12 {main}