SPINEL_PROP_PROTOCOL_VERSION value

Protocol Version Format: `ii` - Read-only Describes the protocol version information. This property contains two fields, each encoded as a packed unsigned integer: `i`: Major Version Number `i`: Minor Version Number The version number is defined by `SPINEL_PROTOCOL_VERSION_THREAD_MAJOR` and `SPINEL_PROTOCOL_VERSION_THREAD_MINOR`. This specification describes major version 4, minor version 3.