Abstract: A method of configuration controlling a hierarchy of data arrays is disclosed, each data array in the hierarchy having at least one version, each version of each data array in the hierarchy being associated with one version of at least one other data array in the hierarchy, each data array comprising at least one data entry, each data entry comprising a plurality of fields, the plurality of fields comprising a version field and at least one characteristic field having a characteristic, the version field indicating which version of that data array the associated characteristic fields belong to. The method comprises the steps of: (i) defining a package of data arrays comprising a predetermined version of at least two data arrays in the hierarchy and in which at least one of the data arrays is to be updated to a new version based on a previous version; and (ii) appending a new version indicator indicative of the new version to each data entry having the previous version in the at least one of the data arrays.