>> "1. Does the wyUpdate work with .net core?"
Not yet. wyUpdate requires Windows Forms (which doesn't exist in a stable form with .NET Core).
We will eventually.
>> "2. I want to give to each developer his own workspace. And to make sure he can't access files of another developer. Is it possible? What's the best way?"
Not sure what you're asking. There are a thousand ways to share / not share files with colleagues. This is more of an IT question.
>> "3. I want to restrict each client to his own directory and make sure they can't access files of others. Possible? What's the best way?"
Are you asking how to use a single license of wyBuid instead of purchasing multiple licenses? Just buy multiple licenses. It's dirt cheap.
>> "4. Will all the previous versions be stored on the server or are they cleaned up automatically?"
No. We don't remove files from your server. That's up to you.
>> "5. What happens in case of update storage becoming unavailable?"
You'll get an error. If you're using HTTP / HTTPS, the error will be 404. Each protocol has a specific error code.