GitHub Copilot retires six models Oct 19: GPT-5.5, Grok 4.5, more
The replacements enable automatically for Enterprise—unless an admin disabled the default. Also: Kiro CLI V3 goes default with persistent cloud sessions.
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The swap list, before Monday
Six models drop across every Copilot surface on Oct 19: GPT-5.5 and GPT-5.4 become GPT-5.6 Sol, GPT-5.4 mini and GPT-5 mini become GPT-5.6 Luna, Gemini 3.7 Flash becomes 3.8 Flash, and Grok 4.5 becomes Grok 4.6. Re-pin any model names hard-coded in your agents, scripts, or CI now.
Enterprise is automatic — unless your admin opted out
For Business and Enterprise, the replacements turn on automatically under default model enablement. But if your org disabled the global default, an admin has to enable the new models in Copilot model policies first, or calls to the retired models will simply fail on the 19th.
The second cull in three weeks
Oct 2 already retired Claude Opus 4.7 (now Opus 5.5), Kimi K2.7 Code (now Kimi K3), and Gemini 3.5 and 3.6 Flash (now 3.8 Flash). If you pin models for reproducibility, budget for re-pinning roughly once a month.
Kiro CLI V3 starts becoming the default
AWS's terminal agent now runs the same harness as its IDE and web app. New: cloud sessions (kiro-cli --cloud) that keep running after you disconnect, opt-in multi-agent Workflows, a spec mode, and memory that persists across sessions. Try it today with kiro-cli --v3; it flips to default for everyone by the end of October.
Copilot in VS Code: parallel agents, worktree cleanup
VS Code 1.141 adds a grid view to run and compare several agent sessions side by side, plus a worktree-cleanup panel that shows how much disk inactive session worktrees are eating and lets you reclaim it — useful if you've been spawning agents all week.