The latest VSCP class and type definitions is always available for download here https://vscp.org/events/
Automatic updates can easily be build by checking the https://vscp.org/events/version.json file programmatically and download a new version of the files if needed.
You find full descriptions, constants, conversions and much more in these files. You are for instance always in the know on data contents and how to convert between available units for measurements.