Are xCBL versions forwards and backwards compatible?
In general yes, key data exist and is transferable between the different version of a document. Starting with xCBL 3.0 a significant number of new data elements where added over what existed in earlier versions. As a result, translating a fully populated xCBL 3.0, 3.5 or 4.0 document to an xCBL 2.0 document will result in a substantial loss of data. However, the core / key data should be translated without loss. Forward translation from xCBL 2.0 to xCBL 3.0 and later versions generally will not result in a loss of data during the translation. Also, appropriate defaults are being defined for mandatory elements in xCBL 3.0 and beyond that do not have a corresponding elements xCBL 2.0. The differences between xCBL 3.0 and 3.5 are minimal and going from 3.0 to a 3.5 document results in no loss of data. Going from a fully populated 3.5 to a 3.0 document will result in some loss due to new elements added in 3.5 documents.. The differences between xCBL 4.0 and 3.0 or 3.5 are minimal. Only new
