Engine Yard Support is adjusting team member schedules to provide additional staffing to assist with the anticipated influx of Support requests tonight and tomorrow morning, and will be doing everything possible to try to minimize the impact of this event upon your applications.
If you have already completed your restarts or reboots this should not affect you. If you need to verify the instances impacted you can visit
https://cloud.engineyard.com/instance-reboots
We encourage you to try and restart or replace instances to the extent possible prior to this maintenance.