I’m posting this today because, like many others in the developer community, I’m frankly shocked and deeply frustrated by Google’s unexpected decision to redirect the “gemini-2.5-pro-preview-03-25” endpoint. This endpoint, clearly labeled with a specific date, suddenly and silently points to the newer “gemini-2.5-pro-preview-05-06” model without any prior announcement or communication to our community. This isn’t just a minor inconvenience; it undermines our trust in the platform, disrupts workflows we’ve carefully built around this endpoint, and honestly leaves us questioning the decision-making that led to such a confusing move.
To be clear, we fully acknowledge Google’s stated documentation about “preview” and “experimental” models being subject to change or removal without notice. But there’s an important gap in this policy: your documentation never addresses specifically dated endpoints. When an endpoint explicitly includes a specific date like “03-25,” the natural, logical assumption from widespread industry norms set by OpenAI, Anthropic, and others, is that it represents a stable and immutable snapshot. The whole point of assigning a clear date label is to signal stability, predictability, and consistency, even if it’s officially still called a “preview.”
This silent redirection has resulted in widespread disruption. Many developers are noting and reporting clear and tangible differences in model performance - not just subtle tweaks, but significant regressions in reasoning abilities, major shifts in style and tone, and measurable changes across well-tested prompts. Entire prompting strategies, applications, and workflows that used to rely consistently on the March 25 checkpoint now suddenly break or behave unexpectedly. Even worse, public benchmarks and evaluations conducted in good faith are now unintentionally misleading or outright incorrect, since they’re unknowingly comparing completely different model versions than their labels suggest.
The resulting confusion has been immediate and widespread. Just go to Reddit, Discord, X, or other forums and you’ll find countless confused and frustrated developers, benchmark maintainers, and researchers struggling to understand what’s going on. The confusion is real, messily public, and incredibly frustrating. While we appreciated the minor clarifications provided by @Logan_Kilpatrick it unfortunately didn’t fully clear things up or directly address the core problem: the unexpected redirection of a clearly dated endpoint.
We completely understand that preview models inherently carry some risk, everyone gets that clearly. But using a clearly labeled date in an endpoint’s name establishes an expectation across our industry. If a model has an explicit date, it logically implies it’s preserved as an immutable checkpoint. That’s exactly how everyone expects dated model naming to behave, preview or not.
This silent endpoint swap hasn’t just confused everyone; it’s led to genuine anger and justified feelings that developers and researchers have been disregarded and blindsided.
With that in mind, we’re strongly urging Google to take direct, concrete steps toward restoring the trust that’s been damaged. In practical terms, we specifically ask that you:
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Immediately and publicly restore the original March 25 checkpoint to its matching dated endpoint (gemini-2.5-pro-preview-03-25).
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If that restoration simply isn’t feasible due to resource concerns, increased confusion, etc., then we urgently need a public clarification and firm commitment moving forward: all clearly dated model checkpoints must permanently remain stable and immutable snapshots representing their stated dates. Only endpoints explicitly labeled “latest” (such as gemini-2.5-pro-preview-latest) should ever redirect or be updated without explicit notice.
Again…we fully accept general risks associated with preview and experimental models. We’re simply asking Google to explicitly adopt and commit to the widely understood and logical industry-standard schema here: dates clearly signal immutability, while only explicitly labeled “latest” endpoints represent versions subject to change or redirection.
That’s it. That’s all we’re asking.
Signed,
A Developer Building on Gemini