Microsoft are phasing this update in offering it to users.
It is being kept separate from normal updates as a "when you are ready" item. Many users have not yet received it.
So far 1903 has had a mixed bag of reception, varying from catastrophe to no problems.
It is a lengthy update and takes around 1 hour in the best of cases to many hours in the worst.
I have decided to let it rest on ice for 2 - 3 months to allow 1903 to become stabilised with time.
What is your experience, have you installed it, if so did you have problems either on installation or thereafter ?