Partial Item Change Tracking and Synchronization

A computer-storage medium that stores instructions, execution of the instructions by a processing unit of a client configures the client to:

• locally cache a data item at the client, the data item comprising a plurality of property groups, each of the property groups mapped to one or more properties of the data item, at least one of the property groups mapped to multiple properties of the data item, the plurality of property groups including at least a follow-up property group and a read status property group;
• send a sync request to a server;
• and
• receive a sync item stream from the server in response to the sync request, the sync item stream including changed property groups in the data item but not the entire data item, one or more properties mapped to the changed property groups having changed since a last sync between the client and the server.

A method of increasing sync rates for a client device, the method comprising:

• transmitting a request from a client device to synchronize one or more data items that have changed after a last synchronization, each of the one or more data items comprising a plurality of modifiable properties, the plurality of modifiable properties in each of the one or more data items divided into a plurality of property groups that includes at least a read property group and a follow-up flag property group, the read property group including a property that indicates whether the data item has been read, the follow-up flag property group including a property that indicates whether a follow-up flag has been set on the data item;
• determining that a first data item of the one or more data items has changed after the last synchronization;
• determining whether the plurality of property groups of the first data item includes a modified property group, wherein a value of a property in the modified property group has changed after the last synchronization;
• and
• synchronizing the modified property group without streaming one or more unmodified property groups in the plurality of property groups of the first data item, wherein none of the properties in the unmodified property groups have values changed after the last synchronization.