Synchronize progress

On the first device: Tap the Settings icon settings icon.  Make sure the reading plan you want to sync is selected! Tap Sync/Share Progress, then Sync another device to this.  Read the alert notice, then tap Proceed.  The 'Mail' application will launch.  Fill out your email address and send the email.  Return to ReadingPlan and tap On to enable syncing.  Back out of Settings; you should see the network activity indicator spin briefly as your current progress is uploaded.

On the second device: Retrieve the email you sent yourself, and select and copy the 'sync key' at the bottom of the message.  In ReadingPlan, Tap the Settings icon settings icon.  Again, make sure the reading plan you want to sync is selected! Tap Sync/Share Progress, then Sync this device with another.  Read the alert notice, then tap Proceed.  You should see the 'sync key' update at the bottom of the screen.  Tap On to enable syncing.  Back out of Settings; you should see the network activity indicator spin briefly as this device is synced with the other.