The next seven weeks hold an unusual number of model retirements and price changes, spread across six platforms. Several apply on one platform but not another: Claude Haiku 4.5 leaves Microsoft Foundry on 15 November but stays Active on the Claude API. Here is the list, in date order, checked against each vendor’s own page.

The calendar

DatePlatformWhat changesReplacement or action
15 Nov 2026Microsoft FoundryClaude Haiku 4.5 retires (both versions)Microsoft lists no replacement. claude-haiku-5-5 is the current Haiku on Foundry
15 Nov 2026Microsoft Foundrycodex-mini (2025-05-16) retiresNone listed
16 Nov 2026GitHub CopilotClaude Opus 4.8, Claude Opus 5 and GPT-5.6 Terra deprecated in all Copilot experiencesOpus 5.5 for the Claude models; GPT-6.1 Sol or GPT-6 Luna for Terra. Opus 4.8 stays for individual subscribers on annual plans
19 Nov 2026Microsoft Foundryo1 and o1-pro retiregpt-5.6-sol
19 Nov 2026Gemini API and Google CloudGemini 3.6 Flash retiresGemini 3.8 Flash, or Gemini 4 Hydrogen, which Google now recommends for 3.8 Flash users
26 Nov 2026Amazon BedrockAI21 Jamba 1.5 Large and Jamba 1.5 Mini reach end of lifeNo replacement found on AWS’s pages
30 Nov 2026Claude APIClaude Sonnet 4.5 (claude-sonnet-4-5-20250929) retiresclaude-sonnet-5-5
30 Nov 2026Google CloudClaude Sonnet 4.5 shuts down (deprecated 29 Sep 2026, existing customers only)Claude Sonnet 5 or 5.5 on Google Cloud
30 Nov 2026Amazon BedrockTwelveLabs Marengo Embed 2.7 reaches end of lifeMarengo Embed 3.0, listed only in ap-northeast-2 so far
30 Nov 2026Claude APIFast mode on Claude Opus 4.8 removed. Requests with speed: "fast" will return an errorOpus 5.5 fast mode. Opus 4.8 itself stays Active
1 Dec 2026Gemini APIGemini 4 Argon and Gemini 4 Carbon introductory prices end: $2/$10 becomes $4/$20 per MTokBudget for the doubling, or move suitable work to Hydrogen
1 Jan 2027Gemini APIGemini 3.8 Flash introductory price ends: $0.75/$3.75 becomes $1.50/$7.50Gemini 4 Hydrogen costs the same from then

What to watch for

Retirement means errors, not a slower model. On Bedrock, AWS says an end-of-life model “becomes completely inaccessible across all AWS Regions”, and migration “doesn’t happen automatically”. Microsoft says retirement dates are not extendable. Anthropic’s fast mode page says requests to the removed configuration “will return an error”. Search your code and infrastructure for these model IDs now, including in prompt templates, configuration files and evaluation harnesses.

The same model can retire on one platform and stay on another. Claude Haiku 4.5 retires on Foundry on 15 November but is still listed as Active on the Claude API, even though its own published floor of 15 October 2026 has passed. Claude Sonnet 4.5 retires on 30 November on both the Claude API and Google Cloud, and Bedrock sets its own date. Check the platform you actually call, not the model vendor’s page alone.

Copilot changes defaults for you. GitHub says the suggested replacements are enabled automatically for Copilot Business and Enterprise unless an administrator has turned off default model enablement. If your organisation pins models for compliance reasons, review the setting before 16 November.

Embeddings are the hard case. Moving from Marengo Embed 2.7 to 3.0 is not a drop-in swap: vectors from different embedding models are not comparable, so the index has to be rebuilt. AWS lists Marengo Embed 3.0 only in ap-northeast-2 so far, which may also be a data-residency question for EU workloads.

Price steps are also deadlines. The 1 December Argon and Carbon step and the 1 January 3.8 Flash step double the cost of unchanged workloads. Put both in your cost model now.

Not this month: Claude Opus 4.5 has a retirement floor of 24 November 2026 on the Claude API, but no deprecation notice. Anthropic commits to at least 60 days’ notice, so it cannot retire in November.

Sources

Further reading