Test new scheduled task
Log in as admin.
Go to Site administration > Server > Tasks > Scheduled tasks
Search for mnet .
Make sure a new scheduled task for MNET is now available:
Background processing for MNET authentication \auth_mnet\task\cron_task
Make sure you are able to edit (Cog icon) and see the logs (That other sheet icon).
deprecation
Run:
php admin/tool/task/cli/schedule_task.php "--execute=\\auth_mnet\\task\\cron_task"
Make sure you don't get any debugging related to deprecation of mnet cron.