I'm trying to update this RetroFit + Otto tutorial, so my code updated is:
IWeather.java
RetroFit 2.+ doesn't allow to return void, so instead of void getWeather(...) I added Call<Weather> getWeather(...).
public interface IWeather {
    @GET("/{latitude},{longitude}")
    Call<Weather> getWeather(@Path("latitude") String latitude,
                             @Path("longitude") String longitude,
                             Callback<Weather> callback);
} 
ForecastClient.java
RetroFit 2.+ has changed his constructor, so the new ForecastClient has the next form. The IllegalArgumentException points to the weather.getWeather(...) method.
public class ForecastClient {
    private static final String BASE_URL = "https://api.darksky.net/forecast/";
    private static final String API_KEY = "******************";
    public static final String API_URL = BASE_URL + API_KEY + "/";
    private static ForecastClient mForecastClient;
    private static Retrofit mRetroAdapter;
    public static ForecastClient getClient() {
        if (mForecastClient == null) {
            mForecastClient = new ForecastClient();
        }
        return mForecastClient;
    }
    private ForecastClient() {
        mRetroAdapter = new Retrofit.Builder()
                .baseUrl(API_URL)
                .addConverterFactory(GsonConverterFactory.create())
                .client(new OkHttpClient())
                .build();
    }
    public void getWeather(String latitude, String longitude, Callback<Weather> callback) {
        IWeather weather = mRetroAdapter.create(IWeather.class);
        weather.getWeather(latitude, longitude, callback);
    }
}
ForecastManager.java
public class ForecastManager {
    private Context mContext;
    private Bus mBus;
    private ForecastClient sForecastClient;
    public ForecastManager(Context context, Bus bus) {
        this.mContext = context;
        this.mBus = bus;
        sForecastClient = ForecastClient.getClient();
    }
    @Subscribe
    public void onGetWeatherEvent(GetWeatherEvent getWeatherEvent) {
        String latitude = Double.toString(getWeatherEvent.getLatitude()).trim();
        String longitude = Double.toString(getWeatherEvent.getLongitude()).trim();
        Callback<Weather> callback = new Callback<Weather>() {
            @Override
            public void onResponse(Call<Weather> call, Response<Weather> response) {
                Log.d(ForecastManager.class.getSimpleName(), response.body().toString());
                mBus.post(new SendWeatherEvent(response.body()));
            }
            @Override
            public void onFailure(Call<Weather> call, Throwable t) {
                Log.e(ForecastManager.class.getSimpleName(), t.getMessage());
            }
        };
        sForecastClient.getWeather(latitude, longitude, callback);
    }
}
I'm receiving a No Retrofit annotation found and I guess the reason is something related with my callback, but it is a RetroFit callback, so I don't understand why the error.
The stacktrace points to the MainActivity, in particular to the Otto's method post() with a java.lang.RuntimeException: Could not dispatch event, caused by the error previously mentioned java.lang.IllegalArgumentException: No Retrofit annotation found. (parameter #3):
MainActivity.java
public class MainActivity extends AppCompatActivity {
    @BindView(R.id.activity_main_textView)
    TextView textView;
    @BindView(R.id.activity_main_button)
    Button button;
    private static final double LATITUDE = **.******;
    private static final double LONGITUDE = **.******;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);
    }
    @OnClick(R.id.activity_main_button)
    public void onClick(View view) {
        BusProvider.getInstace().post(new GetWeatherEvent(LATITUDE, LONGITUDE));
    }
    @Subscribe
    public void onSendWeatherEvent(SendWeatherEvent sendWeatherEvent) {
        Weather weather = sendWeatherEvent.getWeather();
        Currently currently = weather.getCurrently();
        textView.setText(currently.getSummary());
    }
Any clue about where is the error or how should I handle the bus subscriptions, the callback, etcetera?
 
     
     
    