v2.5.3 (Sep 6, 2026)

NumPy 2.5.3 Release Notes

The NumPy 2.5.3 is a patch release that fixes bugs discovered after the 2.5.2
release. Apart from the usual bug and maintenance work, there are a number of
StringDType related fixes for problems discovered during the ongoing string
work in the main branch.

This release supports Python versions 3.12-3.15

Changes

• Casting a fixed-width byte string array (np.bytes_) to StringDType
  now raises TypeError when the bytes are not valid UTF-8. Previously the
  invalid bytes were stored as-is and later caused undefined behavior in
  string operations.

  (gh-32296)

• MaskedArray._fill_value would become stale when ufuncs that change dtype
  left the result holding a fill_value typed for the old dtype. The mismatch
  was silent until something later called _check_fill_value, such as
  .view(), and then a TypeError would be raised. Now, when the copied
  fill_value is no longer valid for the new dtype, fall back to the
  default fill_value for that dtype instead of propagating the stale value.
  This may raise a ComplexWarning if the fill_value is complex and the
  new dtype is real.

  (gh-32423)

Contributors

A total of 9 people contributed to this release. People with a "+" by their
names contributed a patch for the first time.

• Charles Harris
• Iason Krommydas
• James Davies +
• Joren Hammudoglu
• Maanas Arora
• Matti Picus
• Nathan Goldbaum
• Shikhar Goel +
• Yeonho Kim +

Pull requests merged

A total of 27 pull requests were merged for this release.