> For the complete documentation index, see [llms.txt](https://docs.nansen.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.nansen.ai/api/changelog/29-10-2026-chain-retirement.md).

# 29-10-2026: Chain retirement schedule

Chain retirement dates for Nansen API, MCP and CLI.

Nansen is retiring support for the following chains across the API, MCP and CLI.

| Retirement date   | Chains                                                                                                           |
| ----------------- | ---------------------------------------------------------------------------------------------------------------- |
| November 25, 2026 | Algorand, Aptos, Chiliz, Gravity, Katana, Stacks, Stellar, Viction, Mantra, Citrea, TON, Sonic, Plasma, Bitlayer |
| February 1, 2027  | Optimism, Arc, Starknet, Sei, Mantle, Sui                                                                        |

Affected chain values remain available until retirement on endpoints that currently support them. This notice does not add chain support to other endpoints or deprecate an entire multi-chain endpoint.

## Prepare your integration

Before each retirement date, remove the affected chains from saved API requests, MCP prompts and tool arguments, CLI commands, scheduled jobs and watchlists. Use a supported chain for new requests.

After retirement, single-chain requests for a retired chain will return an error, without silently returning empty data or substituting another chain. Requests that select all chains, including default all-chain rankings, will no longer include retired-chain data. Update integrations that rely on those rankings even if they never name an affected chain explicitly.

After a chain retires, requests that explicitly include it will fail validation, including mixed lists of supported and retired chains. For example, `["ethereum", "ton"]` will be rejected after TON retires on November 25, 2026; it will not return partial results for Ethereum. Remove retired chains from the list before retrying.

The same schedule applies when an AI assistant calls Nansen through MCP or when you use the Nansen CLI. Changing clients does not preserve access to a retired chain.


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