Last updated: 2026-09-30
Changelog archive — September 2026
Every AI agent release we logged in September 2026: 7 daily entries across the platforms we track, each linked to its full write-up. The main changelog shows the latest releases; this page lists the whole month.
- 2026-09-30 — Sonnet 5.5, OpenClaw 2026.9.7, GPT-6.1 Sol, IronClaw 1.4.1
Claude Sonnet 5.5 launches at $2/$10 and becomes Claude Code's default Sonnet (2.1.284–2.1.286, which also start sessions in auto mode by default); OpenClaw 2026.9.7 adds verified backups and automatic rollback for failed updates and removes Tasks and TaskFlow; OpenAI releases GPT-6.1 Sol at GPT-6 Sol's price; IronClaw 1.4.1 ships the Google OAuth fix and a Wasmtime security update. - 2026-09-27 — Claude Code model controls, Kilo 7.8, Hermes 0.21.5
Claude Code 2.1.282–2.1.283 adds managed model allow/deny controls, /doctor prompt-audit and a prose-width setting; Claude opens plugin submissions; Kilo Code 7.8 streams a real browser into localhost previews; Hermes 0.21.5 rolls up 460 PRs with notes deferred; IronClaw 1.4.1-rc.2 fixes Google OAuth activation; Jev Router lands on OpenRouter. - 2026-09-24 — Jev ships a new model class, Opus 5.5 undercuts Opus 5
A model that returns typed decisions instead of text, a cheaper Opus, two new GPT-6 tiers, Grok 4.7 at Grok 4.6 prices, and an OpenClaw release you should not install on macOS yet. - 2026-09-19 — Claude Code reads AGENTS.md, Kilo Code drops KiloClaw
Cross-harness instruction files arrive in Claude Code, KiloClaw leaves the Kilo editor, and Hermes repairs the state.db damage v0.21.0 did. - 2026-09-11 — one Claude Code release broke two whole configurations
v2.1.265 shipped two regressions that each broke an entire class of setup, and one of them took three days and three releases to fix. - 2026-09-06 — GPT-6 Astra lands on Fable 5.1's exact price
Two flagships launched two days apart at exactly $10/$50 with roughly a million tokens of context. Meanwhile Gemini 3.8 Flash undercuts both by 13× on input. - 2026-09-01 — Fable 5.1 and Mythos 5.1 land at $10/$50, and tool_choice breaks
Anthropic's new top tier keeps Fable 5's price and adds a 1M default context — but tool_choice: any now returns 400, and zero data retention is not available on either model.