Latest Update Conflict with PDF Light Viewer

The most recent UpdraftPlus update has caused a conflict with the PDF Light Viewer plugin. The PDF plugin quits working and you can only login to the backend of the site in recovery mode. Any ideas on what can be done?

Here is the Error message:

An error of type E_ERROR was caused in line 152 of the file /home/rrichmo/michaeldunncenter.org/wp-content/plugins/pdf-light-viewer/vendor/webdevstudios/cmb2/init.php. Error message: Uncaught Error: Call to undefined function cmb2_bootstrap() in /home/rrichmo/michaeldunncenter.org/wp-content/plugins/pdf-light-viewer/vendor/webdevstudios/cmb2/init.php:152

Stack trace:
#0 /xxx/xxx/xxx.org/wp-includes/class-wp-hook.php(307): CMB2_Bootstrap_221->include_cmb('')
#1 /xxx/xxx/xxx.org/wp-includes/class-wp-hook.php(331): WP_Hook->apply_filters(NULL, Array)
#2 /xxx/xxx/xxx.org/wp-includes/plugin.php(476): WP_Hook->do_action(Array)
#3 /xxx/xxx/xxx.org/wp-settings.php(598): do_action('init')
#4 /xxx/xxx/xxx.org/wp-config.php(81): require_once('/home/rrichmo/m...')
#5 /xxx/xxx/xxx.org/wp-load.php(50): require_once('/home/rrichmo/m...')
#6 /xxx/xxx/xxx.org/wp-admin/admin.php(34): require_once('/home/rrichmo/m...')
#7 /xxx/xxx/xxx.org/wp-admin/network/admin.php(13): require_once('/home/rrichmo/m...')
#8 /xxx/xxx/xxx.org/wp-admin/networ