This might be related to the changes in the promises that is described in more detail at CesiumJS is switching from when.js to native promises-- Which will be a breaking change in 1.92 .
Could you describe in more detail what it means when you say that the code “does not work anymore”? Do you see rendering artifacts, or nothing rendered at all? Or do you see crashes or error messages in the console (if so: which messages) …? Maybe the CesiumJS core team can give more specific hints based on that, beyond the things that are mentioned in the linked thread.