Google's John Mueller has responded to a question about whether core updates roll out in stages or follow a fixed sequence. This question was prompted by a common observation that rankings tend to shift in waves during a rollout period, often lasting several weeks. Mueller explained that Google does not formally define or announce stages for core updates and that these updates involve broad changes across multiple systems, which can require a step-by-step rollout rather than a single deployment. He also noted that there is no single mechanism for governing how all core updates are released and that updates reflect the work of different teams and systems. This suggests that the volatility observed during core updates may correspond to incremental changes across different systems rather than single reset followed by adjustments.