Problem with UltimateExpress bindings

I am trying to update existing bindings for express and move it to ultimate-express support
(GitHub - dimdenGD/ultimate-express: The Ultimate Express. Fastest http server with full Express compatibility, based on µWebSockets.).
This is my fork: GitHub - the-man-with-a-golden-mind/rescript-ultimate-express: Experimental bindings to ultimate-express

It looks fine. However, there is one issue with importing the module.
The example (example/App.res) is compiling to:

import * as UltimateExpress from "ultimate-express";
import UltimateExpress$1 from "ultimate-express";

var app = UltimateExpress$1();
var router = UltimateExpress.Router();

Importing with * does not work here, so I get an error message: UltimateExpress.Router is not a function.

Any clues on how I can solve it?