You can now define a cutoff behavior for your maintenance tasks using AWS Systems Manager Maintenance Windows, which allows you to stop or continue ongoing tasks when the cutoff time is reached. This provides DevOps and IT engineers with more control on the cutoff behavior to ensure disruptive tasks are not run outside the desired period. For instance, while registering an Automation task with a maintenance window, you can now set up the cutoff behavior to cancel ongoing tasks. This would ensure that no new task invocations are started when the cutoff time is reached.
Source:: Amazon AWS