Hardcopy drivers must be able to work with earlier levels as well as future levels of drivers across a network. Notice that there are several possible driver version numbers:
The numbering scheme for drivers is as follows:
New Driver
For drivers reading data from an earlier version of the driver, the data must be interpreted (by using the lVersion number as a guide to its format) and any missing data must set to the device defaults. For drivers reading data from a later version of the driver, as much data as possible should be read and the rest ignored. This implies that later versions of the driver only add new driver data fields at the end of the data.