Anthropic set a firm date on something developers have known was coming for months. The original Claude 4 models, the same Sonnet and Opus variants that launched in May 2025 as the company's first "Claude 4" generation, will stop accepting requests on June 15, 2026. After that date, any API call referencing claude-sonnet-4-20250514 or claude-opus-4-20250514 will return an error. The window to act is shorter than it looks: with the holiday weekend ahead and release cycles closing out the month, two weeks is a tight runway for teams with production dependencies.
A Year of Rapid Iteration
When Claude Sonnet 4 and Opus 4 debuted on May 22, 2025, they represented the company's sharpest models at the time. Both supported extended thinking, improved computer use, and a step-change in agentic coding performance. Within months, they were joined by incremental successors. Claude Opus 4.1 arrived in August 2025. Claude Sonnet 4.5 and Opus 4.5 shipped in September and November respectively. By February 2026, Claude Sonnet 4.6 and Opus 4.6 had arrived, each bringing a 1M token context window and stronger agentic reasoning. The cadence has since compressed further, with Opus 4.7 landing in April and Opus 4.8 shipping on May 28, just three days ago.
The two original Claude 4 models have been live for roughly thirteen months, a lifespan that now sits at the shorter end of Anthropic's retirement windows. They were genuinely capable when they shipped, but each successive version has delivered improvements in benchmark performance, context handling, and tool-use reliability that make the originals increasingly redundant for production workloads. Anthropic has been consistent about retiring earlier model IDs once their successors are well established, following the same pattern it applied to Claude Haiku 3 in April and to Sonnet 3.7 and Haiku 3.5 in February.
June 15 Retirement: Key Facts
- Retirement dateJune 15, 2026
- Affected model IDsclaude-sonnet-4-20250514, claude-opus-4-20250514
- Recommended Sonnet replacementclaude-sonnet-4-6-20260217
- Recommended Opus replacementclaude-opus-4-7-20260416 or claude-opus-4-8-20260528
- Migration effortOne-line model string change for most integrations
- Also expiring soonOpus 4.6 fast mode (~June 27)
What Developers Need to Do
The migration is simpler than most API changes. For most integrations, swapping the model string is sufficient. Developers running claude-sonnet-4-20250514 can replace it with claude-sonnet-4-6-20260217, which delivers stronger agentic search performance, the 1M token context window at no premium, and pricing that holds at $3/$15 per million input/output tokens. Those running claude-opus-4-20250514 can upgrade to claude-opus-4-7-20260416 or the newly released claude-opus-4-8-20260528. Opus 4.8 adds adaptive thinking (which triggers reasoning only when a turn actually needs it), mid-conversation system message support, and a lower minimum cacheable prompt length of 1,024 tokens.
One caveat applies to Opus migrations. Both Opus 4.7 and 4.8 introduced API-breaking changes relative to their predecessors, specifically around sampling parameter behavior and restrictions on assistant message prefilling. The Anthropic migration guide documents these differences in detail, and most teams will need to verify their usage of temperature, top_p, and top_k parameters before deploying the upgrade, since non-default values for these now return a 400 error on the newer models.
"Once a model is deprecated, migrate all usage to a suitable replacement before the retirement date. Requests to models past the retirement date will fail." Anthropic model deprecations policy
What Else Expires in June
June 15 is not the only expiration date worth tracking. Fast mode for Claude Opus 4.6, which Anthropic deprecated on May 28 alongside the Opus 4.8 launch, carries a removal window of approximately 30 days, putting that cutoff around June 27. Teams using Opus 4.6 fast mode for accelerated inference will need to migrate to fast mode on Opus 4.8, which Anthropic has priced at roughly three times cheaper than the equivalent Opus 4.7 fast mode rate. For teams on Opus 4.8 Max plan on claude.ai, fast mode is now the default.
The 1M token context window beta for Claude Sonnet 4 and Sonnet 4.5 was already retired on April 30. Any workflow that relied on the extended context window on those older model IDs should have already migrated to Sonnet 4.6, where the 1M window is generally available at standard pricing with no beta header required.
The cumulative picture is of Anthropic tightening its model surface at pace, retiring older IDs as successors mature. For teams running Claude in production, the practical lesson from the past several months is clear: track the model IDs your integrations are pinned to, and set a review calendar for any model that is approaching its first anniversary in production. At the current cadence, that review is no longer a theoretical exercise. The Claude Opus 4.8 release last week brought another round of capability improvements, and Sonnet 4.6 from February already offers substantially better agentic reasoning than the original Claude 4 Sonnet that is now being retired.
Find current model IDs and pricing on the Claude models page. Anthropic's official deprecation schedule is maintained in the Claude Platform documentation.
