Dropbox checks if any changes were made to your offline folders when you open the Offline tab. If changes were made, Dropbox syncs these changes to your device when your device is connected to WiFi. When your device is not connected to WiFi, changes are indicated by a yellow "!", and you can tap to update them manually. If you'd like folders to update using data (when you're not connected to WiFi), go to your settings and toggle Use Cellular Data to on.
Automatic syncing while the app is in the background is not currently supported. The only exception is when Android devices are connected to power, offline files sync in the background.
You can make up to 100 folders available offline.
A folder can't be saved for offline use if:
There can be a few different explanations for a red "x" on the folder icon, including:
A yellow exclamation point means that a newer version of your folder is available. Tapping the refresh icon on iOS or Update all button on Android syncs these changes.
When the Dropbox app is open, any changes automatically sync to your phone. If these changes are greater than 20 MB, you can decide whether you’d like to wait for WiFi or sync the changes anyway. If you'd like folders to update using data (when you're not connected to WiFi), go to your settings and toggle Use Cellular Data to on.
Yes. Folders that are marked to be available offline are stored locally on your device. If you have less than 500 MB of storage available, syncing automatically stops.
No, this feature is not currently supported.