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This article summarizes the latest model router releases and major documentation updates, including new supported models, routing features, deployment options, and observability.
September 2026
Session affinity for Chat Completions (preview)
Chat Completions applications can now supply an opaque session ID to ask model router to attempt the same eligible model across related conversation turns. Session affinity preserves existing eligibility and fallback behavior and reports whether a request initialized, retained, or switched the model association. For setup and verification guidance, see Use model router.
Per-request routing metadata (preview)
Chat Completions responses from model router identify the serving model and can now include preview observability metadata when the client opts in to the preview response contract. The metadata reports the routing mode, routing-trace latency, ordered model attempts, HTTP status, and returned errors. Multiple attempts can show when automatic fallback occurred for an individual request. For setup and parsing guidance, see Monitor model router.
Model router expands to 32 regions
Model router is now available in 32 Azure regions. The four additional regions are Canada Central, North Europe, Norway East, and UAE North. North Europe and Norway East support both Global Standard and Data Zone Standard deployments. Canada Central and UAE North support Global Standard deployments only. For the full list, see Supported regions.
August 2026
Model router expands to 28 regions
Model router is now available in 28 Azure regions. Global Standard was available in all 28 regions, while Data Zone Standard was available in 21. For the full list, see Supported regions.
Model refresh adds GPT-5.6 family and Claude Opus 4.8
Model router version 2025-11-18 now supports 27 models. The routing pool adds gpt-5.6-sol, gpt-5.6-terra, and gpt-5.6-luna version 2026-07-09, and claude-opus-4-8 version 1. To use claude-opus-4-8 with model router, first deploy it to your Foundry resource.
The routing pool removes the retired gpt-5-chat, gpt-5.2-chat, gpt-5.3-chat, DeepSeek-V3.1, and claude-opus-4.1 models.
Configuring a custom model subset is optional. If you previously configured a subset that contains any of these removed models, replace them with models from the current supported models list. If you use the default routing pool, no action is required.
Agentic routing expands to more model providers
For agentic requests, model router can now select eligible open-source (OSS) and Anthropic models in addition to OpenAI models. Model and tool compatibility determine which models are eligible for each request. For more information, see Use model router with Foundry agents.
July 2026
Regional expansion
Model router is now available in three additional regions: Australia East, South India, and West US 3, with both Global Standard and Data Zone Standard deployment types. For the full list of supported regions, see the Model router concepts guide.
May 2026
Seven new models added
Model router now supports 28 models. Version 2025-11-18 adds support for seven new models: gpt-5.4, gpt-5.4-mini, gpt-5.4-nano, gpt-5.3-chat, gpt-5.5, claude-opus-4-7, and grok-4.1-fast-reasoning. To use claude-opus-4-7 in your model router deployment, you need to first deploy it to your Foundry resource (see Deploy and use Claude models). grok-4.1-fast-reasoning model router support is in preview.
Increased quota limits
Model router quota limits increased across Tier 1 through Tier 6 for both GlobalStandard and DataZoneStandard deployment types. For the updated limits, see Quotas and limits.
March 2026
Four new models added
Version 2025-11-18 of model router adds support for four new models: gpt-5.2, gpt-5.2-chat, Deepseek-v3.2, and claude-opus-4-6. To use claude-opus-4-6 in your model router deployment, you need to first deploy it to your Foundry resource (see Deploy and use Claude models). Deepseek-v3.2 and claude-opus-4-6 model router support is in preview.
Automatic failover
Model router now includes built-in automatic failover. When a routed model experiences endpoint instability, model router transparently redirects the request to the next most appropriate model, so transient issues with any single model don't disrupt your application. Failover is enabled for default model router deployments — no additional configuration is required. For more information on the failover feature and how it works with routing mode and model subsets, see the Model router concepts guide.
November 2025
Anthropic models added
Version 2025-11-18 of model router adds support for three Anthropic models: claude-haiku-4-5, claude-opus-4-1, and claude-sonnet-4-5. To include these in your model router deployment, you need to first deploy them yourself to your Foundry resource (see Deploy and use Claude models).
Model router GA version
A new model router model is now available. Version 2025-11-18 includes support for all underlying models in previous versions, as well as 10 new language models.
It also includes new features that make it more versatile and effective.
- Routing profiles let you skew model router's choices to optimize for quality or cost while maintaining a baseline level of performance.
- Model router supports custom subsets: you can specify which underlying models to include in routing decisions. This gives you more control over cost, compliance, and performance characteristics.
- Model router supports Global Standard and Data Zone Standard deployment types.
For more information on model router and its capabilities, see the Model router concepts guide.
August 2025
New version of model router (preview)
Model router now supports GPT-5 series models.
Model router for Microsoft Foundry is a deployable AI chat model that automatically selects the best underlying chat model to respond to a given prompt. For more information on how model router works and its advantages and limitations, see the Model router concepts guide. To use model router with the Completions API, follow the How-to guide.
May 2025
Model router (preview)
Model router for Foundry is a deployable AI chat model that automatically selects the best underlying chat model to respond to a given prompt. For more information on how model router works and its advantages and limitations, see the Model router concepts guide. To use model router with the Completions API, follow the How-to guide.