Set the amount of time before your next shift start time that you want to be reminded.
Allow push notifications from OpenSimSim on your smartphone, (iOS or Android).
Enable & Set Reminder
Login to the Mobile App and go to More Menu > Account > Notification Settings > Shift Reminders
Tap on Shift Reminders and toggle to enable. The time selector will display.
Set the desired reminder time, for example 2 hours before shift start time. Save when done.
In my example, received at 4pm for 6pm start time.