cwork101 / timeline
Timeline
Model releases, product launches, renames, betas going GA, and retirements — in one dated sequence, because the ecosystem's history is currently spread across a dozen changelogs.
2026
- Academy
anthropic.com/learn redirects to academy.claude.com
Anthropic Academy consolidates onto its own domain. The old path issues a permanent redirect — worth checking if you have it linked in internal documentation.
source ↗ - PlatformMilestone
Sonnet 5 introductory pricing becomes permanent
The $2/$10 per million token rate, announced at launch as introductory through 31 August 2026, becomes the standard price. The increase to $3/$15 scheduled for 1 September 2026 is cancelled.
source ↗ - Deprecation
Claude Opus 4.1 retired on the Claude API
Deprecated 5 June 2026. Still available on Amazon Bedrock and Google Cloud, which run their own retirement schedules — the clearest current example of first-party and partner lifecycles diverging.
source ↗ - ModelMilestone
Claude Opus 5 released
The current recommended default: 1M-token context, 128K output, and a May 2026 reliable knowledge cutoff — the most recent of any current model.
source ↗ - Company
AI for Science applications close
Anthropic's grant round offering up to $30,000 in API credits to as many as 50 scientific projects closed to applications.
source ↗ - ModelMilestone
Claude Sonnet 5 released
A 1M-token context window at $2 in / $10 out per million tokens — a third cheaper than Sonnet 4.6 — described as the most agentic Sonnet model yet, with performance close to Opus 4.8.
source ↗ - ProductMilestone
Claude Science released in beta
A desktop research workbench for scientists on macOS and Linux, shipping analysis specialists for genomics, single-cell, proteomics, structural biology and cheminformatics, with provenance on every result.
source ↗ - Deprecation
Claude Sonnet 4 and Claude Opus 4 retired
Deprecated 14 April 2026. Both remain available on partner clouds — Sonnet 4 on Bedrock and Google Cloud, Opus 4 on Google Cloud.
source ↗ - ModelMilestone
Claude Fable 5 and Claude Mythos 5
A fourth naming tier arrives above Opus. Fable 5 is generally available for long-running agents, with adaptive thinking always on. Mythos 5 is invitation-only for defensive cybersecurity through Project Glasswing.
source ↗ - Deprecation
Claude Haiku 3 retired
Deprecated 19 February 2026 with a 60-day notice period, then retired. Replacement: Claude Haiku 4.5.
source ↗ - Deprecation
Claude Sonnet 3.7 and Claude Haiku 3.5 retired
Two retirements on the same day, closing out the Claude 3 line on the first-party API. Both remain available on Amazon Bedrock and Google Cloud.
source ↗ - Deprecation
Claude Opus 3 retired
Deprecated 30 June 2025, retired six months later. Replacement: Claude Opus 4.8.
source ↗
2025
- Feature
Agent Skills announcement updated
The Skills announcement is revised, reflecting expanded support across the Claude apps, Claude Code, the API and the Agent SDK.
source ↗ - Deprecation
Claude Sonnet 3.5 retired
Both snapshots — 20240620 and 20241022 — retired after deprecation on 13 August 2025. Replacement: Claude Sonnet 4.6.
source ↗ - FeatureMilestone
Agent Skills announced
Folders of instructions, scripts and resources that Claude loads on demand. Released with a skill-creator tool and the anthropic/skills marketplace, and published as a cross-platform open standard.
source ↗ - ModelMilestone
Claude Haiku 4.5 released
Coding performance comparable to Claude Sonnet 4 at a third the cost and more than twice the speed. Still the cheapest current model, and the last one using the pre-4.7 tokenizer and explicit extended thinking.
source ↗ - Deprecation
Claude 2, Claude 2.1 and Claude Sonnet 3 retired
Deprecated on 21 January 2025 with six months' notice, then retired.
source ↗
2024
- PlatformMilestone
Model Context Protocol released as an open standard
Anthropic open-sources MCP, a protocol for connecting assistants to external tools and data, with reference servers and SDKs. It becomes the standard way Claude reaches anything outside itself.
source ↗ - Deprecation
Claude 1.x and Instant retired
The first generation of Claude models is retired, having been deprecated on 4 September 2024. Recommended replacement is now Claude Haiku 4.5.
source ↗ - ModelMilestone
The Opus / Sonnet / Haiku naming begins
Claude 3 introduces the three-tier scheme — Opus for the most capable model, Sonnet for the balanced one, Haiku for the fastest — reused by every later generation.
2023
- ModelMilestone
Claude launches
Anthropic releases the first Claude models to early access partners, alongside a public API waitlist.
Nothing of that kind recorded yet.