code: func handleVersion(s *rpcServer, cmd interface{}, closeChan <-chan struct{}) (interface{}, error) {
  	result := map[string]btcjson.VersionResult{
  		"btcdjsonrpcapi": {
  			VersionString: jsonrpcSemverString,
  			Major:         jsonrpcSemverMajor,
  			Minor:         jsonrpcSemverMinor,
  			Patch:         jsonrpcSemverPatch,
  		},
  	}
  	return result, nil
  }
docs: // handleVersion implements the version command.
  //
  // NOTE: This is a btcsuite extension ported from github.com/decred/dcrd.