Hi Pranav,
FreeMASTER (desktop tool) version 3.x is backward compatible with all previous versions of the embedded driver. We recommend using latest official release for each platform:

Note that for for S12Z, latest version is 2.0. It is fully supported by FreeMASTER 3.x with the drawback that GUI side will be limited to the functionalities supported in FreeMASTER 2.x. In case you need to use extra functionalizes added in version 3 you can refer to this thread (see attached files and comments).
Best regards,
Iulian