More than an update, this is a real revolution. The changes are drastic with a new model of data collection and processing. The new Analytics 4 seems to use machine learning , for machine learning and to provide useful information to users. The main novelty is in user tracking , rather than Universal Analytics' piecemeal per-device analysis.
Google's goal is to overcome and aggregate Web and App events into a single property, this responds to today's needs and allows a better understanding of the impact of Marketing actions.