v2.1.0

Teams SDK for .NET 2.1 is the first stable release of the redesigned SDK. It replaces the plugin-oriented model of 2.0 with a plain ASP.NET Core app, so your bot composes with the dependency injection, middleware, and logging you already use.

New apps should target 2.1 directly. Start with the quickstart. If you're coming from 2.0, the migration guide covers the API changes in detail, and the announcement post explains the reasoning behind them.

Important

2.0.x will be deprecated. It remains on NuGet and still receives fixes for now, but it is on a path to end of support and will not get new features. Plan your migration to 2.1. We'll announce the deprecation timeline separately.

What's new

• Agentic identity — bring an Agent 365 identity to Teams as an AI teammate that calls APIs as itself.
• Multi-flow OAuth — each connection is a named flow with its own callbacks, so multiple connections stay isolated.
• Built-in state — ConversationState and UserState via options.UseState(), backed by IDistributedCache.
• OpenTelemetry — the pipeline emits traces, metrics, and logs through standard .NET primitives.
• Bot Framework v4 compatibility — run an existing IBot on the new infrastructure without rewriting handlers.

Packages

Package	Version
Microsoft.Teams.Apps	2.1.0
Microsoft.Teams.Core	2.1.0
Microsoft.Teams.Cards	2.1.0
Microsoft.Teams.Apps.BotBuilder	2.1.0

Packages no longer available

The following 2.0 packages have no 2.1 equivalent and must be replaced:

Removed package	Alternative
Microsoft.Teams.AI / Microsoft.Teams.AI.Models.OpenAI	Microsoft.Extensions.AI
Microsoft.Teams.Extensions.Graph	Microsoft.Graph
Microsoft.Teams.Apps.Testing	Standard .NET DI mocking
Microsoft.Teams.Common (logging, HTTP)	Microsoft.Extensions.Logging and HttpClient via DI
Microsoft.Teams.Plugins.*	Plugin architecture removed. Use standard ASP.NET Core middleware and DI