1. A machine implemented method comprising: receiving, by a first data processing device during synchronization of structured data of a data class with a second data processing device, a version number corresponding to a second software component of the second data processing device, wherein the second software component is configured to cause the retrieval and storage of the structured data in the second data processing device during synchronization; comparing, by the first data processing device, the version number corresponding to the second software component with a version number corresponding to a first software component of the first data processing device, wherein the first software component is configured to cause the retrieval and storage of the structured data in the first data processing device during synchronization; and determining, by the first data processing device based upon the comparison of version numbers, how to synchronize the data class.