Anthropic has released a June 2026 update detailing significant changes to its Claude model lineup. The company launched two new top-tier models, Fable 5 and Mythos 5, on June 9th, touting improvements in coding, vision, and finance reasoning. However, just three days later, Anthropic suspended access to both Fable 5 and Mythos 5, advising users to revert to Opus 4.8. Additionally, Anthropic retired Claude Sonnet 4 and Claude Opus 4 on June 15th, meaning any requests to these specific model IDs will now fail outright, with Sonnet 4.6 and Opus 4.8 recommended as replacements. AI
IMPACT New model releases and suspensions create uncertainty for developers and users relying on Anthropic's platform.
RANK_REASON Frontier-lab model release with subsequent suspension and retirement of older models. [lever_c_demoted from frontier_release: ic=1 ai=1.0]
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