We announced the deprecation of the Claude Sonnet 4.5 model (claude-sonnet-4-5-20250929), with retirement on

DeprecationSep 30, 20263 days agoUnverifiedAdded Oct 2, 2026

We announced the deprecation of the Claude Sonnet 4.5 model (claude-sonnet-4-5-20250929), with retirement on the Claude API scheduled for November 30, 2026. We recommend migrating to Claude Sonnet 5.5. Read more in Model deprecations.

Topics: LLMs, Developer tools

Anthropic's release notes

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Every Claude Platform release

Date	Release	Type
Sep 285 days ago	We've launched Claude Sonnet 5.5 (claude-sonnet-5-5) unverified Update	Update
Sep 285 days ago	Code written for Claude Sonnet 5 can break on Claude Sonnet 5.5 in five ways unverified Update	Update
Sep 285 days ago	Thinking blocks that Claude Sonnet 5.5 produces work only in the account that produced them, or in an account unverified Update	Update
Sep 258 days ago	Build plugins for Claude unverified Update	Update
Sep 249 days ago	We're expanding which refusals are billed to include refusals that arrive before any output when unverified Update	Update
Sep 249 days ago	We're resuming billing for refusals that arrive before any output when stop_details.category is "bio" unverified Pricing	Pricing
Sep 249 days ago	The Compliance API local session endpoints are out of beta for Claude for Microsoft 365 sessions in Excel unverified Beta	Beta
Sep 249 days ago	The Compliance API Activity Feed no longer returns file names, project document names, or artifact titles unverified Update	Update

Also shipped on Sep 30, 2026

Anthropic in September 2026

Date	Company	Release	Product	Type
Sep 303 days ago	New Relic	Place pipeline processors anywhere you need them with Pipeline Control unverified New RelicPreview	New Relic	Preview
Sep 303 days ago	New Relic	The updated version of Pathpoint is now available in Public Preview unverified New RelicPreview	New Relic	Preview
Sep 303 days ago	Astronomer	The new Astro experience is now live for all Organizations unverified AstronomerAstroPreview	Astro	Preview
Sep 303 days ago	Astronomer	The Astro IDE is generally available unverified AstronomerAstroGA	Astro	GA
Sep 303 days ago	Cloudflare	Containers - New scheduling policy for Containers to configure image and instance from Durable Objects unverified CloudflareCloudflare developer platformBeta	Cloudflare developer platform	Beta
Sep 303 days ago	Cloudflare	Containers - Snapshot and restore Container filesystem unverified CloudflareCloudflare developer platformBeta	Cloudflare developer platform	Beta

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Also shipped on Sep 30, 2026

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