Siaqodb and IOS mobile app

I am trying to use the last version Siaqodb for a cross-platform mobile app. For Android, everything works fine, but I encountered some problem with IOS. I installed the last version from nugget (4.0.2.29) and I am using an example from Siaqodb documentation http://siaqodb.com/tutorial2/.

`class SiaqodbFactory
{
private static Siaqodb instance;

   public static Siaqodb GetInstance()
   {
          if (instance == null)
          {
                 string dbPath= Environment.GetFolderPath (Environment.SpecialFolder.Personal);
                 instance = new Siaqodb(dbPath);
          }
          return instance;
   }

}`

And I am getting error “Cannot resolve symbol Siaqodb” in line “ instance = new Siaqodb(dbPath);”
In the IOS project references I can see only SiaqodbPortable but this package consists only ISiaqodb interface and doesn’t consist Siaqodb class. For instance, the Android project references consist SiaqodbPortable and Siaqodb (MonoAndroid) and I don’t have any problem to instantiate Siaqodb.

Maybe anybody knows what I am doing wrong?