When you acquire a module on the marketplace, that module is available on your download. From you downloads you can get the latest update which might not be compatible with your actual NexoPOS version. You might then need to download a prior version espcially if you want to downgrade your module.
Here you'll learn how to download prior version for a specific module.
In order to access to those downloads, you need open your account and head to your download.
From you downloads, you'll see a menu named "All Downloads".
By clicking on that, you'll land on the list of all the versions released for that specific module. You just now have to download the version of your choice.