Change the locale language inside the app

_App.java

public class App extends Application {
    public void onCreate(){
        super.onCreate();

        LocaleUtils.setLocale(new Locale("iw"));
        LocaleUtils.updateConfig(this, getBaseContext().getResources().getConfiguration());
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        LocaleUtils.updateConfig(this, newConfig);
    }
}

_BaseActivity.java

public class BaseActivity extends AppCompatActivity {
    public BaseActivity() {
        LocaleUtils.updateConfig(this);
    }
}

LocaleUtils.java

import android.app.Application;
import android.content.res.Configuration;
import android.content.res.Resources;
import android.os.Build;
import android.view.ContextThemeWrapper;

import java.util.Locale;

public class LocaleUtils {

    public static final String LAN_SPANISH      = "es";
    public static final String LAN_PORTUGUESE   = "pt";
    public static final String LAN_ENGLISH      = "en";

    private static Locale sLocale;

    public static void setLocale(Locale locale) {
        sLocale = locale;
        if(sLocale != null) {
            Locale.setDefault(sLocale);
        }
    }

    public static void updateConfig(ContextThemeWrapper wrapper) {
        if(sLocale != null && Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
            Configuration configuration = new Configuration();
            configuration.setLocale(sLocale);
            wrapper.applyOverrideConfiguration(configuration);
        }
    }

    public static void updateConfig(Application app, Configuration configuration) {
        if(sLocale != null && Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN_MR1) {
            //Wrapping the configuration to avoid Activity endless loop
            Configuration config = new Configuration(configuration);
            config.locale = sLocale;
            Resources res = app.getBaseContext().getResources();
            res.updateConfiguration(config, res.getDisplayMetrics());
        }
    }
}

I followed this gist to implement changing language within app functionality. But recently I found that even if the font size is set in sp format, the font size doesn't change with the system font settings, unless I change BaseActivity back to AppCompatActivity....