On Android devices, Unplugged can automatically sync overnight Daily or Weekly.
On iOS devices, scheduled replication is not supported. As an alternative, Unplugged supports sync reminders. These work similarly to scheduled sync, but when a sync is due, instead of actually performing the sync, the Unplugged icon will be marked with the number 1 in a red circle as a reminder to launch it and sync manually. This is similar to other native apps running on iOS. For example, email or Facebook uses the APNS (Apple's notification service) to badge the app with a number on the icon. The data is not pushed to the phone but is pulled down once the app is opened (hence the small 'loading' icon for each of these apps).
However, programmatic replication as part of the design can be triggered. This means that a sync can be attempted “automatically” when a user opens an application, or on any event (button tap, navigation, etc.).