Automated conversion of versioned data collections

Various computing components (such as devices, operating environments, and processes) may communicate by exchanging instances of a data collection, such as a class or data structure. However, the definition of the data collection may evolve to specify different numbers, types, properties, and orderings of the items in the data collection, and it may be difficult to verify the structure and contents of an instance received from another component and possibly of a different version. This difficulty may be mitigated by exchanging versioning information about the instance (e.g., as part of the communications wire protocol) and by allocating the converting such that the sender may downconvert to earlier versions requested by a recipient, while the recipient may upconvert to later versions than a version provided by a sender. These techniques may promote the accuracy and consistency of information exchange among many components that operate on different versions of the data collection.