Use the "Occassionally-Connected Computing" tag for "OCC" issues such as cloud-device synchronization and offline device operations.
"Occassionally-Connected Computing" or "OCC" is the main paradigm of our day for phones and other devices:
Users can utilize the data system, on the device, even when the device is not connected. When connection to the cloud resumes, some sort of synchronization systems aligns the cloud and devices.
All major apps of our era (the major social media apps, etc) are "OCC" systems. Most BAAS systems (whether Parse, Firebase, etc) have OCC elements, or indeed, are entirely conceived as an OCC solution.