Highlights

This release introduces the new 2025 stable style (#4558), stabilizing
the following changes:

• Normalize casing of Unicode escape characters in strings to lowercase (#2916)
• Fix inconsistencies in whether certain strings are detected as docstrings (#4095)
• Consistently add trailing commas to typed function parameters (#4164)
• Remove redundant parentheses in if guards for case blocks (#4214)
• Add parentheses to if clauses in case blocks when the line is too long (#4269)
• Whitespace before # fmt: skip comments is no longer normalized (#4146)
• Fix line length computation for certain expressions that involve the power operator (#4154)
• Check if there is a newline before the terminating quotes of a docstring (#4185)
• Fix type annotation spacing between * and more complex type variable tuple (#4440)

The following changes were not in any previous release:

• Remove parentheses around sole list items (#4312)
• Generic function definitions are now formatted more elegantly: parameters are
  split over multiple lines first instead of type parameter definitions (#4553)

Stable style

• Fix formatting cells in IPython notebooks with magic methods and starting or trailing
  empty lines (#4484)
• Fix crash when formatting with statements containing tuple generators/unpacking
  (#4538)

Preview style

• Fix/remove string merging changing f-string quotes on f-strings with internal quotes
  (#4498)
• Collapse multiple empty lines after an import into one (#4489)
• Prevent string_processing and wrap_long_dict_values_in_parens from removing
  parentheses around long dictionary values (#4377)
• Move wrap_long_dict_values_in_parens from the unstable to preview style (#4561)

Packaging

• Store license identifier inside the License-Expression metadata field, see
  PEP 639. (#4479)

Performance

• Speed up the is_fstring_start function in Black's tokenizer (#4541)

Integrations

• If using stdin with --stdin-filename set to a force excluded path, stdin won't be
  formatted. (#4539)