The overall version of the complete set of MIB's that is
currently supported by the software running on the device.
It returns an integer which relates to the last software
release that contained changes to the supported AT Enterprise
MIB definition files. For example, if the currently loaded
software release on the the device is 5.3.1-03 but the
Enterprise MIB's have not changed since 5.3.1-01, then the
value returned will be 5030101 (5.03.01-01).