--- title: "Cloudflare DNS settings API drops the foundation_dns field on November 23, 2026: 2026-11-23 | Harbyn" description: "Cloudflare DNS settings API drops the foundation_dns field on November 23, 2026, effective Nov 23, 2026; replacement: nameservers.type." canonical: "https://harbyn.com/changes/cloudflare/2026-07-27-foundation-dns-boolean-deprecated" last-updated: 2026-10-08 --- # Cloudflare DNS settings API drops the foundation\_dns field on November 23, 2026 Markdown version of . Retirement - Cloudflare. high severity. Announced. Upcoming. From October 26, 2026 the zone and account DNS settings API gradually returns nameservers.type "cloudflare.advanced" for Advanced Nameservers, so clients treating that field as a closed enum must accept the new value. From November 23, 2026 the API stops returning foundation\_dns and rejects PATCH requests that include it; each rollout takes about seven days. 29 days left: the deadline is Nov 23, 2026. ## Facts | Fact | Value | | --- | --- | | Vendor | [Cloudflare](https://harbyn.com/vendors/cloudflare.md) | | Kind | Retirement | | Severity | high | | Status | Announced | | Announced | Jul 27, 2026 | | Effective | Nov 23, 2026 | | Added to Harbyn | Oct 8, 2026 | | Lead time | 46 days of warning | | Symbols | `foundation_dns` | | Replacement | `nameservers.type` | | Review | Reviewed by a person, extracted by a model | ## Find it in your code ```sh npx harbyn scan ``` This change names no identifier the scanner can match line by line, so the scan tells you whether your repository uses Cloudflare, from its packages and API hosts. Nothing leaves your machine. ## Sources Where this event comes from: the page we read, when we read it, and the hash of that snapshot. - (deprecations, fetched 2026-10-08 17:16 UTC, sha256 `d7c038e2553509de3d70846a452398fc4acd4d5c7740643722821ae47e76cfb0`) ## Related changes ### More from Cloudflare - [Zone Settings Batch API end of life moved to March 31, 2027](https://harbyn.com/changes/cloudflare/2026-07-27-zone-settings-batch-api-end-of-life-extended.md) (Retirement, effective Mar 31, 2027) - [Account creation API rejects names longer than 65 characters](https://harbyn.com/changes/cloudflare/2026-07-22-account-name-limit-enforcement.md) (Behavior change, effective Sep 27, 2026) - [Legacy Workers KV namespace API routes stop working October 15, 2026](https://harbyn.com/changes/cloudflare/2026-07-15-workers-kv-legacy-namespace-routes-reach-end-of-life.md) (Retirement, effective Oct 15, 2026) - [CIDR-encoded Zero Trust route endpoints and Tunnel connections field removed](https://harbyn.com/changes/cloudflare/2026-07-09-zero-trust-route-endpoints-and-tunnel-connections-field-changes.md) (Retirement, effective Oct 5, 2026) ### Changes at other vendors - [OpenRouter: arcee-ai/trinity-large-thinking expire 2026-10-26](https://harbyn.com/changes/openrouter/2026-10-23-arcee-ai-trinity-large-thinking-expires-2026-10-26.md) (effective Oct 26, 2026) - [Google Cloud Run and Functions: Node.js 20 runtime decommission](https://harbyn.com/changes/google-cloud/2026-10-08-node-js-20-runtime-decommission.md) (effective Oct 30, 2026) - [Mistral AI: Z.ai GLM 5.2 (zai-glm-5-2) retires on Mistral on October 31, 2026](https://harbyn.com/changes/mistral/2026-09-29-z-ai-glm-5-2-deprecated-and-scheduled-for-retirement.md) (effective Oct 31, 2026) - [Fireworks AI: DeepSeek V4 Flash 0731 retires from Serverless Training November 2](https://harbyn.com/changes/fireworks/2026-10-18-upcoming-serverless-training-deprecation-deepseek-v4-flash-0731.md) (effective Nov 2, 2026) [All upcoming deadlines](https://harbyn.com/deadlines.md)