Google’s John Mueller responded to a question about whether major updates were rolling out in stages or following a fixed sequence. His answer offers some clarity on how core updates are rolled out and also what certain core updates actually are.
Question about timing and volatility of core updates
An SEO asked on Bluesky if core updates behave as a single rollout that is then refined over time or if the different updated parts are rolled out at different stages.
The question reflects a common observation that rankings tend to move in waves over the course of a deployment period, which often lasts several weeks. This has led to speculation that updates could be rolled out incrementally rather than all at once.
They request:
“Given the timing, I want to ask a question related to kernel updating. Usually we see waves of volatility throughout the 2-3 weeks of a deployment. Generally speaking, are different parts of the kernel updated at different times? Or is everything reset at the beginning and then repeated based on the results?”
Major updates may require a step-by-step rollout
Mueller explained that Google does not formally define or announce the stages of major updates. He noted that these updates involve significant changes across multiple systems, which may require a step-by-step rollout rather than a one-time rollout.
He replied:
“We don’t typically announce ‘milestones’ for major updates. Because these are large, broad changes to our search algorithms and systems, they sometimes need to work step by step, rather than all at once. (This is also why they can take a while to be fully operational.)”
Updates depend on the systems and teams involved
Mueller then added that there is no single mechanism governing how all major updates are released. Instead, updates reflect the work of different teams and systems, which may vary from update to update.
He explained:
“In short, I guess there isn’t a single ‘master update machine’ that gets clicked on (each update has the same flow), but rather we make the changes based on what the teams have been working on, and these systems and components may change from time to time.
Major updates can be rolled out gradually rather than all at once
Mueller’s explanation suggests that the waves of volatility seen during major updates could correspond to incremental changes in different systems rather than a single reset followed by adjustments. Because updates are tied to multiple components, deployment can progress in stages as those systems are updated and fully operational.
This reflects a process where some changes are complex and require a more nuanced step-by-step rollout, rather than being released all at once, which may explain why ranking changes may appear uneven over the rollout period.
Connecting to Google spam update?
I don’t think it’s a coincidence that March Core Update followed closely after the recent March 2026 Anti-Spam Update. The reason I think this is because it makes sense for anti-spam to be part of the set of changes in a core algorithm update. This is why Googlers sometimes say that a core update should surface more relevant content and less low-quality content.
So when Google announces a spam update, it stands out because either Google is making a major change to the infrastructure that Google’s core algorithm runs on, or the spam update is intended to eliminate specific forms of spam before rolling out an update to the core algorithm, to clear the table, so to speak. And that’s what seems to have happened with recent spam and core algorithm updates.
Comparison with the first Google updates
In the beginning, about 25 years ago, Google did an update every month, providing the ability to see if new pages are indexed and ranked, as well as see how existing pages are performing. The first few days of the update saw large-scale fluctuations that we (WebmasterWorld forum members) called the Google Dance.
At the time, it felt like updates were just Google adding more pages and reranking them. Then, during the 2003 update in Florida, it became apparent that the ranking systems were being changed and that the fluctuations could last for months. This was probably the first time the SEO community noticed another type of update that was probably closer to a core algorithm update.
In my opinion, one way to look at it is that Google’s indexing and ranking algorithms are like software. And then there is also hardware and software that is part of the infrastructure on which the indexing and ranking algorithms run (like the operating system and hardware of your desktop or laptop computer).
This is an oversimplification, but it is useful for me to visualize what an update to a basic algorithm could be. Most of it, if not all, has to do with the indexing and filing part. But I think sometimes there are infrastructure type changes happening that improve the indexing and ranking part.
Featured image by Shutterstock/A9 STUDIO
