AI agent frameworks have been renamed, merged, archived and re-versioned so often since 2024 that a tutorial from last year may point at a product that no longer exists under that name. This page is a dated record of the main releases, renames, foundation moves and end-of-support dates across the agent frameworks, managed agent platforms and agent protocols that teams most often ask about. It answers the questions people type into search: what happened to AutoGen, what happened to Vertex AI Agent Builder, when the OpenAI Assistants API shuts down, and which versions are still supported. It is written for developers, architects and anyone who has to keep an agent estate current. Every entry cites the owner's own announcement, documentation, changelog or repository. Last checked: 2026-11-15.
This is an independent reference page from NHI Mgmt Group based on public provider documentation; it is not sponsored or endorsed by any provider.
Key takeaways
- Microsoft consolidated its two frameworks. Microsoft Agent Framework 1.0 shipped on 3 April 2026 as the successor to Semantic Kernel and AutoGen, and the AutoGen repository now says it is archived and no longer maintained by Microsoft.
- Vertex AI became Gemini Enterprise Agent Platform. Google Cloud announced on 22 April 2026 that the platform is "the evolution of Vertex AI" and that all Vertex AI services and roadmap will be delivered through it.
- The OpenAI Assistants API shuts down on 26 August 2026. OpenAI's deprecations page gives 26 August 2025 as the notice date and names the Responses API and Conversations API as replacements.
- Protocols moved to neutral foundations. A2A joined the Linux Foundation on 23 June 2025, and MCP was contributed to the new Agentic AI Foundation on 9 December 2025.
- December 2026 is the next cliff. LangChain 0.3 and LangGraph 0.4 leave maintenance in December 2026.
How to read this timeline
Entries are in date order. Where several events share a date or month they are listed alphabetically by product, and order is never a ranking. Each row names the source type so you can check it yourself. The timeline includes only events with a dated official source: an owner's blog post, press release, documentation page, changelog or repository file. Where the owner gives only a month, the month is shown. All tables are as of 15 November 2026.
Three kinds of change matter most for planning:
- Renames: the code may keep working but documentation, package names and search results move. Old names linger in tutorials.
- Successions: a new product replaces an old one and the old one is archived, put into maintenance or folded in. Code has to migrate.
- Dated shutdowns and support ends: after the date an API stops responding or security fixes stop. These are the dates to put in a risk register.
For a side-by-side view of what each framework does today, see the AI Agent Frameworks and Platforms Hub (2026); for managed platforms, see AI Agent Platforms Compared. This page covers only what changed and when.
Timeline: 2022 to 2024
| Date | Product | Event | Source type |
|---|---|---|---|
| Late 2022 | LangChain | Starts as a single Python package on a personal GitHub account; LangChain, Inc. is co-founded in early 2023 | LangChain About page |
| 2024 | OpenAI Swarm | OpenAI releases Swarm, an experimental multi-agent SDK, later succeeded by the Agents SDK | OpenAI announcement, 11 March 2025 |
| November 2024 | Model Context Protocol (MCP) | Anthropic open sources MCP | Linux Foundation press release, 9 December 2025 |
| 5 November 2024 | MCP specification | First dated specification revision, 2024-11-05 | MCP specification repository |
Before 2025 the field was dominated by general LLM application libraries. Most of the names teams rely on today, including the OpenAI Agents SDK, Google ADK, A2A, Amazon Bedrock AgentCore and Microsoft Agent Framework, arrived in 2025.
Timeline: 2025
| Date | Product | Event | Source type |
|---|---|---|---|
| 11 March 2025 | OpenAI Agents SDK and Responses API | OpenAI releases the Responses API, built-in web search, file search and computer use tools, and the open source Agents SDK as the successor to Swarm. It says it will deprecate the Assistants API once the Responses API reaches feature parity, with a target sunset of mid-2026 | OpenAI announcement |
| 26 March 2025 | MCP specification | Specification revision 2025-03-26 | MCP specification repository |
| April 2025 | A2A protocol | Google launches the Agent2Agent protocol | Linux Foundation press release |
| 9 April 2025 | Google Agent Development Kit (ADK) | Google introduces ADK at Google Cloud NEXT 2025 as an open source framework, the same one powering agents in Agentspace, with deployment to Vertex AI Agent Engine | Google Developers Blog |
| 18 June 2025 | MCP specification | Specification revision 2025-06-18 | MCP specification repository |
| 23 June 2025 | A2A protocol | The Linux Foundation launches the Agent2Agent Protocol Project, with Google Cloud contributing the protocol | Linux Foundation press release |
| 30 July 2025 | LlamaIndex | llama-index-core 0.13.0 removes deprecated agent classes (including FunctionCallingAgent, AgentRunner and OpenAIAgent); users move to workflow-based FunctionAgent, CodeActAgent, ReActAgent and AgentWorkflow | LlamaIndex changelog |
| 26 August 2025 | OpenAI Assistants API | Deprecation notice; shutdown set for 26 August 2026 | OpenAI deprecations page |
| 8 September 2025 | LlamaIndex | llama-index-core 0.14.0 moves to llama-index-workflows 2.0 | LlamaIndex changelog |
| September 2025 | Pydantic AI | Reaches V1 with an API stability commitment until V2 | Pydantic AI upgrade guide |
| 29 September 2025 | Claude Agent SDK | Anthropic renames the Claude Code SDK to the Claude Agent SDK, saying the harness behind Claude Code can power many other kinds of agents | Claude article; SDK changelog (0.1.0) |
| October 2025 | Microsoft Agent Framework | Microsoft introduces Agent Framework | Microsoft Agent Framework blog, 3 April 2026 |
| 6 October 2025 | OpenAI AgentKit | OpenAI launches AgentKit: Agent Builder (beta), Connector Registry (beta rollout), ChatKit (generally available) and new evals capabilities (generally available) | OpenAI announcement |
| 13 October 2025 | Amazon Bedrock AgentCore | AgentCore becomes generally available, with Runtime, Gateway, Identity, Memory and Observability, and support for VPC, AWS PrivateLink, CloudFormation and tagging across services | AWS What's New |
| 20 October 2025 | LangChain and LangGraph | Both reach 1.0.0. LangChain introduces create_agent and middleware; LangGraph deprecates create_react_agent in favour of it. Both 1.0 lines are designated long-term support releases | LangChain changelog and release notes |
| 25 November 2025 | MCP specification | Specification revision 2025-11-25 | MCP specification repository |
| 9 December 2025 | Agentic AI Foundation | The Linux Foundation forms the Agentic AI Foundation with three founding projects: MCP (contributed by Anthropic), goose (Block) and AGENTS.md (OpenAI) | Linux Foundation press release |
Timeline: 2026
| Date | Product | Event | Source type |
|---|---|---|---|
| 19 February 2026 | Microsoft Agent Framework | Reaches Release Candidate for .NET and Python; Microsoft publishes migration guidance for Semantic Kernel and AutoGen projects and calls Agent Framework their successor | Microsoft Agent Framework blog |
| 10 March 2026 | LangGraph | Version 1.1.0 adds opt-in type-safe streaming and invoke | LangChain changelog |
| 3 April 2026 | Microsoft Agent Framework | Version 1.0 for .NET and Python: "stable APIs, and a commitment to long-term support", with MCP support included and A2A 1.0 support described as coming soon | Microsoft Agent Framework blog |
| 22 April 2026 | Gemini Enterprise Agent Platform | Google Cloud launches the platform as the evolution of Vertex AI, with Agent Studio, an upgraded ADK, Agent Runtime, Agent Identity, Agent Registry and Agent Gateway | Google Cloud blog |
| 12 May 2026 | LangChain and LangGraph | langgraph 1.2.0 (node timeouts, error handlers, DeltaChannel) and langchain 1.3.0 | LangChain changelog |
| 19 May 2026 | Google ADK (Python) | Version 2.0.0 released | ADK Python changelog |
| 23 June 2026 | Pydantic AI | V2.0 stable release, collecting the breaking changes V1's stability promise held back | Pydantic AI upgrade guide |
| 28 July 2026 | MCP specification | Schema revision 2026-07-28 is the version referenced in the specification repository's README | MCP specification repository |
| 26 August 2026 | OpenAI Assistants API | Scheduled shutdown date | OpenAI deprecations page |
| 1 September 2026 | LangChain | Version 1.4.0 ships MCP support in the langchain.mcp namespace (beta), replacing langchain-mcp-adapters | LangChain changelog |
| 11 November 2026 | LangChain | Version 1.5.0; langchain 1.5 and langchain-core 1.8 drop Python 3.10 | LangChain changelog |
| 12 November 2026 | Google ADK (Python) | Version 2.14.1, the latest entry in the changelog when checked | ADK Python changelog |
| December 2026 | LangChain 0.3 and LangGraph 0.4 | End of MAINTENANCE support (security patches and critical fixes) | LangChain release policy |
Renames and successions
| Earlier name or product | Current name or successor | When | What it means in practice |
|---|---|---|---|
| AutoGen (Microsoft) | Microsoft Agent Framework | Successor named February 2026; 1.0 on 3 April 2026 | The AutoGen repository is archived; Microsoft points existing users to its AutoGen migration guide |
| Claude Code SDK (Anthropic) | Claude Agent SDK | 29 September 2025 | New package name from SDK version 0.1.0; same agent harness |
langchain-mcp-adapters | langchain.mcp namespace | 1 September 2026 | MultiServerMCPClient is replaced by MCPAdapter; a migration guide is published |
langgraph.prebuilt.create_react_agent | langchain.agents.create_agent | 20 October 2025 | Deprecated, not removed; LangChain's policy keeps deprecated features working through 1.x |
| LangSmith Deployment (earlier LangGraph Platform paths) | LangSmith Agent Server | Rename note in current docs | Same hosting product; search results and bookmarks may use any of the names |
| Semantic Kernel (Microsoft) | Microsoft Agent Framework | Successor named February 2026; 1.0 on 3 April 2026 | The Semantic Kernel README says "Semantic Kernel is now Microsoft Agent Framework" |
| Swarm (OpenAI) | OpenAI Agents SDK | 11 March 2025 | Swarm was experimental; the Agents SDK is its production successor |
| Vertex AI, including its agent building tools (Google Cloud) | Gemini Enterprise Agent Platform | 22 April 2026 | Google says all Vertex AI services and roadmap are delivered through the Agent Platform rather than as a standalone service |
Foundation moves are a different kind of change: the protocol keeps its name but governance moves to a neutral body. A2A moved to the Linux Foundation on 23 June 2025, and MCP moved to the Linux Foundation's new Agentic AI Foundation on 9 December 2025. The MCP specification repository's licence file says the project is "undergoing a licensing transition from the MIT License to the Apache" licence, so check the current terms if you redistribute it.
Deprecations and end-of-support dates
| Product or version | Status as of 15 November 2026 | Key date | Replacement |
|---|---|---|---|
| AutoGen | Archived; README says it is no longer maintained by Microsoft and warns that vulnerabilities may remain unaddressed | Successor 1.0: 3 April 2026 | Microsoft Agent Framework |
| LangChain 0.3 | MAINTENANCE (security patches and critical fixes) | Until December 2026 | LangChain 1.x |
| LangGraph 0.4 | MAINTENANCE (security patches and critical fixes) | Until December 2026 | LangGraph 1.x |
| LlamaIndex legacy agent classes | Removed in llama-index-core 0.13.0 | 30 July 2025 | Workflow-based agents and AgentWorkflow |
| OpenAI Assistants API | Past its scheduled shutdown date | 26 August 2026 | Responses API and Conversations API |
| Pydantic AI V1 APIs deprecated in V2 | Deprecated, to be removed in V3 | V2.0: 23 June 2026 | V2 APIs per the upgrade guide |
| Semantic Kernel | Succeeded by Microsoft Agent Framework | Successor 1.0: 3 April 2026 | Microsoft Agent Framework |
Products are listed alphabetically. Where an owner has published a long-term support policy, it is worth recording alongside these dates. LangChain and LangGraph 1.0 stay ACTIVE until 2.0 and then get at least one year of MAINTENANCE. Microsoft describes Agent Framework 1.0 as carrying "a commitment to long-term support". Pydantic AI publishes a version policy that ties breaking changes to major versions.
Status and licence at a glance
For each product in this timeline, as of 15 November 2026. Licences are taken from the repository licence file; managed services have no open source licence.
| Product | Owner | Kind | Licence | Latest dated milestone above |
|---|---|---|---|---|
| A2A protocol | Linux Foundation (contributed by Google) | Protocol | Apache 2.0 | Linux Foundation project, 23 June 2025 |
| Amazon Bedrock AgentCore | AWS | Managed platform | Managed service | Generally available, 13 October 2025 |
| AutoGen | Microsoft | Framework | MIT (code); CC BY 4.0 (documentation) | Archived; successor 1.0 on 3 April 2026 |
| Claude Agent SDK | Anthropic | SDK | MIT | Renamed, 29 September 2025 |
| Gemini Enterprise Agent Platform | Google Cloud | Managed platform | Managed service | Launched, 22 April 2026 |
| Google ADK (Python) | Framework | Apache 2.0 | 2.14.1, 12 November 2026 | |
| LangChain | LangChain, Inc. | Framework | MIT | 1.5.0, 11 November 2026 |
| LangGraph | LangChain, Inc. | Runtime | MIT | 1.2.0, 12 May 2026 |
| LlamaIndex | LlamaIndex | Framework | MIT | Core 0.14.0, 8 September 2025 |
| Microsoft Agent Framework | Microsoft | Framework | MIT | 1.0, 3 April 2026 |
| Model Context Protocol | Agentic AI Foundation (originated at Anthropic) | Protocol | Transitioning from MIT to Apache 2.0 | Schema revision 2026-07-28 |
| OpenAI Agents SDK | OpenAI | SDK (Python and JavaScript/TypeScript) | MIT | Released, 11 March 2025 |
| Pydantic AI | Pydantic | Framework | MIT | V2.0, 23 June 2026 |
| Semantic Kernel | Microsoft | SDK | MIT | Succeeded; successor 1.0 on 3 April 2026 |
What happened to AutoGen and Semantic Kernel?
Microsoft merged them. The Agent Framework 1.0 announcement says the framework combines Semantic Kernel's enterprise foundations with AutoGen's orchestration patterns in one open source SDK for .NET and Python, and Microsoft publishes a migration guide for each. The AutoGen README now states that AutoGen "is now archived and no longer maintained by Microsoft" and tells new users to start with Microsoft Agent Framework. The Semantic Kernel README opens with "Semantic Kernel is now Microsoft Agent Framework". The community fork AG2 continues separately under its own maintainers. For identity, tool approval and telemetry controls in the new framework, see the Microsoft Agent Framework and AutoGen security guide.
What happened to Vertex AI Agent Builder?
On 22 April 2026 Google Cloud announced Gemini Enterprise Agent Platform and described it as "the evolution of Vertex AI". The announcement says that "all Vertex AI services and roadmap evolutions will be delivered exclusively through the Agent Platform, rather than as a standalone service". The old agent-builder product URL now opens the Agent Platform page. The announcement groups the platform into Build (Agent Studio, ADK, Agent Garden), Scale (Agent Runtime, Memory Bank, Sessions, Sandbox), Govern (Agent Identity, Agent Registry, Agent Gateway, threat and anomaly detection) and Optimize. It does not attach GA or preview labels in the post, so check the release notes for each component's stage. For controls, see the Google Vertex AI Security Guide.
When does the OpenAI Assistants API shut down?
OpenAI's deprecations page lists the Assistants API with a notice date of 26 August 2025 and a shutdown date of 26 August 2026, and recommends the Responses API and Conversations API, with a migration guide. The March 2025 announcement had set a target sunset of mid-2026. The open source Agents SDK, available for Python and JavaScript/TypeScript, sits on top of the Responses API and also supports Chat Completions and other model providers, according to its README. AgentKit, launched on 6 October 2025, adds a visual Agent Builder and ChatKit on top. See the Securing OpenAI Agents SDK and Responses API Guide.
Other 2025 to 2026 platform and SDK milestones
- Amazon Bedrock AgentCore: generally available on 13 October 2025. AWS says AgentCore works with any open source framework and names CrewAI, LangGraph, LlamaIndex, Google ADK and the OpenAI Agents SDK as examples. See the AWS Bedrock AgentCore Security Guide.
- Claude Agent SDK: renamed from the Claude Code SDK on 29 September 2025; the Python SDK changelog marks the rename at 0.1.0. See the Claude Agent SDK Security Guide.
- LangChain and LangGraph: 1.0 on 20 October 2025, with built-in MCP from 1.4.0. The full version history is in LangChain and LangGraph, and controls in the LangChain and LangGraph Security Guide.
- LlamaIndex: legacy agent classes removed on 30 July 2025 in favour of workflow-based agents. See the LlamaIndex Security Guide.
- Pydantic AI: V1 in September 2025 and V2.0 on 23 June 2026, with a published upgrade guide and version policy. See the Pydantic AI Security Guide.
Protocol milestones affect every framework at once. MCP has dated specification revisions (2024-11-05, 2025-03-26, 2025-06-18, 2025-11-25 and 2026-07-28 in the repository), and frameworks pin to one or more of them. See the MCP Security Guide and the A2A Protocol Security Guide.
Where identity and security fit
Renames and successions are an identity problem as much as a code problem. An archived framework still running in production keeps its API keys, service accounts and OAuth grants, and it stops receiving fixes. A migration to a successor usually means new credentials, new token scopes and a new place to store them. When you move a workload off a retired product, inventory and revoke the old credentials as part of the change, not after it. The Securing Agent Frameworks Guide covers the control set that stays the same across frameworks, and Agent Frameworks vs Managed Agent Platforms explains how responsibility shifts when you move from a library to a managed platform.
Practitioner checklist
- Inventory every agent framework, SDK and platform in use, with the exact package names and versions, and match each against the renames and successions table.
- Put the dated items in your risk register: Assistants API shutdown (26 August 2026), LangChain 0.3 and LangGraph 0.4 end of maintenance (December 2026).
- Find any production use of archived AutoGen or of Semantic Kernel and plan the move to Microsoft Agent Framework using Microsoft's migration guides.
- Update internal documentation and onboarding material that still uses old names such as Claude Code SDK, Vertex AI Agent Builder or LangGraph Platform.
- When migrating, issue fresh credentials for the new workload and revoke the old API keys, service accounts and OAuth grants.
- Record which MCP specification revision each framework and server supports, and re-test when either side moves.
- Subscribe to each owner's changelog or release feed for the products you depend on, and review this list at least quarterly.
Standards and references
- Microsoft: Microsoft Agent Framework Version 1.0
- Google Cloud: Introducing Gemini Enterprise Agent Platform
- OpenAI: Deprecations
- OpenAI: New tools for building agents
- AWS: Amazon Bedrock AgentCore is now generally available
- Linux Foundation: Formation of the Agentic AI Foundation
- Linux Foundation: Agent2Agent Protocol Project launch
- LangChain: Python changelog
Related NHI Mgmt Group resources: AI Agent Frameworks and Platforms Hub (2026) · AI Agent Platforms Compared · Securing Agent Frameworks Guide · LangChain and LangGraph