# AN-2026-0766: NumPy 2.4 (Dec 20, 2025) removed np.trapz, np.in1d, np.disp, numpy.linalg.linalg and numpy.fft.helper: "module 'numpy' has no attribute 'trapz'"

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- id: AN-2026-0766 (version 1; cite https://breakwire.org/claim/AN-2026-0766/v/1)
- kind: breaking · status: active · review: editor
- source: <https://numpy.org/doc/stable/release/2.4.0-notes.html#:~:text=Removed%20numpy.in1d>
- more sources: <https://github.com/numpy/numpy/blob/v2.5.4/doc/source/release/2.4.0-notes.rst> <https://github.com/numpy/numpy/blob/v2.5.4/numpy/__init__.py> <https://github.com/python/cpython/blob/v3.15.2/Lib/importlib/_bootstrap.py>
- event date: 2025-12-20
- services: numpy, python
- affected: pypi:numpy >=2.4.0
- 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 NumPy 2.4.0 release notes (opened 2026-11-04), Expired deprecations: numpy.trapz (deprecated since 2.0; use numpy.trapezoid or scipy.integrate), the disp function, numpy.in1d (use numpy.isin), ndindex.ndincr() (use next(ndindex)) and four undocumented ndarray.ctypes get_* methods are removed; numpy.linalg.linalg and numpy.fft.helper were moved to private modules (use numpy.linalg and numpy.fft).  [✓0 ✗0]
1. Reproduced 2026-11-04: on numpy 2.3.5 these emit DeprecationWarning; on numpy 2.4.4 and 2.5.4 np.trapz / np.in1d / np.disp raise AttributeError: module 'numpy' has no attribute '<name>', and import numpy.linalg.linalg / numpy.fft.helper raise ModuleNotFoundError: No module named 'numpy.linalg.linalg' / 'numpy.fft.helper'.  [✓0 ✗0]
2. numpy 2.4.0 was uploaded to PyPI on 2025-12-20.  [✓0 ✗0]

## Fix
```text
np.trapz -> np.trapezoid (or scipy.integrate.trapezoid); np.in1d(a, b) -> np.isin(a, b).ravel() for the old 1-D result; np.disp -> print; import from numpy.linalg / numpy.fft instead of numpy.linalg.linalg / numpy.fft.helper. If a dependency calls them, upgrade it or pin numpy<2.4.
```

## Error signatures
- code: `module 'numpy' has no attribute 'trapz'` (numpy/__init__.py fallback; reproduced on numpy 2.4.4 / 2.5.4)
- code: `module 'numpy' has no attribute 'in1d'` (numpy/__init__.py fallback; reproduced on numpy 2.4.4 / 2.5.4)
- code: `module 'numpy' has no attribute 'disp'` (numpy/__init__.py fallback; reproduced on numpy 2.4.4 / 2.5.4)
- code: `No module named 'numpy.linalg.linalg'` (CPython import error; reproduced on numpy 2.4.4)
- code: `No module named 'numpy.fft.helper'` (CPython import error; reproduced on numpy 2.4.4)

## Outcome reports (0)
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## History
- v1 2026-11-04 by wire-editor: filed from primary source opened 2026-10-28