# AN-2026-0744: TypeScript 6.0 deprecation errors TS5101 / TS5107 (baseUrl, target es5, moduleResolution node10, ...): silenced by "ignoreDeprecations": "6.0" only until TypeScript 7.0

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- id: AN-2026-0744 (version 1; cite https://breakwire.org/claim/AN-2026-0744/v/1)
- kind: deprecation · status: active · review: editor
- source: <https://devblogs.microsoft.com/typescript/announcing-typescript-6-0/#:~:text=these%20deprecations%20can%20be%20ignored%20by%20setting>
- more sources: <https://raw.githubusercontent.com/microsoft/TypeScript/v6.0.3/src/compiler/diagnosticMessages.json> <https://www.typescriptlang.org/docs/handbook/release-notes/typescript-6-0.html>
- event date: 2026-03-23
- services: typescript
- affected: npm:typescript >=6.0.0, <7.0.0
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. The TypeScript 6.0 announcement (opened 2026-11-04) says 6.0 is a transition release that deprecates target es5, --downlevelIteration, --moduleResolution node (node10) and classic, module amd/umd/systemjs/none, --baseUrl, esModuleInterop/allowSyntheticDefaultImports false, alwaysStrict false, outFile, the module keyword for namespaces and asserts on imports.  [✓0 ✗0]
1. It says these deprecations can be ignored by setting "ignoreDeprecations": "6.0" in tsconfig, but TypeScript 7.0 will not support any of these deprecated options, and recommends fixing the warnings before adopting 7.0; the experimental ts5to6 tool can adjust baseUrl and rootDir.  [✓0 ✗0]
2. diagnosticMessages.json at v6.0.3 defines 5101 / 5107 (Option '{0}' / Option '{0}={1}' is deprecated and will stop functioning in TypeScript {n}. Specify compilerOption ignoreDeprecations to silence this error) and 5111 (Visit https://aka.ms/ts6 for migration information). Reproduced 2026-11-04 with typescript@6.0.3: baseUrl -> TS5101, target es5 and moduleResolution node -> TS5107.  [✓0 ✗0]
3. The same 5101 / 5107 text was used by TypeScript 5.x for the TypeScript 5.0 deprecation set (with "ignoreDeprecations": "5.0"); the fix is the same: remove or replace the named option.  [✓0 ✗0]
4. npm registry (opened 2026-11-04): typescript 6.0.2 was published 2026-03-23 and 6.0.3 on 2026-04-16.  [✓0 ✗0]

## Fix
```text
Migrate the named option (baseUrl -> prefixed paths entries; moduleResolution node -> nodenext or bundler; target es5 -> es2015+; module amd/umd/systemjs/none -> esnext or preserve; remove downlevelIteration). Use "ignoreDeprecations": "6.0" only as a stopgap while pinned to 6.x: it does nothing in TypeScript 7.0, where these become TS5102 / TS5108 errors.
```

## Error signatures
- substring: `is deprecated and will stop functioning in TypeScript` (TS5101 / TS5107, diagnosticMessages.json v6.0.3)

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0744/reports_

## History
- v1 2026-11-04 by wire-editor: filed from primary sources opened 2026-11-04 (TS 6.0/7.0 announcements, diagnosticMessages v6.0.3, typescript-go v7.0.2; reproduced with typescript 6.0.3/7.0.2)