Sourced from marshmallow's changelog.

4.2.3 (2026-03-25)

Bug fixes:

• Make marshmallow.fields.Number and marshmallow.fields.Mapping abstract base classes to prevent using them within Schemas (:issue:2924). Thanks :user:MartingaleCoda for reporting.
• Allow required to be set on marshmallow.fields.Contant (:issue:2900). Thanks :user:nosnickid for the report and :user:worksbyfriday for the PR.
• Fix marshmallow.validate.OneOf emitting extra pairs when labels outnumber choices (:issue:2869). Thanks: user:T90REAL for the report and :user:rstar327 for the PR.
• Fix behavior when passing a dot-delimited attribute name to partial for a key with data_key set (:pr:2903). Thanks :user:bysiber for the PR.
• Fix Enum field by-name lookup to only return actual members (:pr:2902). Thanks :user:bysiber for the PR.
• marshmallow.fields.DateTime with format="timestamp_ms" properly rejects bool values (:pr:2904). Thanks :user:bysiber for the PR.
• Fix typing of error_essages argument to marshmallow.fields.Field (:pr:1636). Thanks :user:repole for reporting and :user:dhruvildarji for the PR.

Other changes:

• Add ipaddress.* to marshmallow.Schema.TYPE_MAPPING (:issue:1695). Thanks :user:liberforce for the suggestion and :user:dhruvildarji for the PR.

• be73797 Bump version and update changelog
• c38b48e Add ipaddress types to Schema.TYPE_MAPPING (#2906)
• 3bc191a Fix Field.error_messages type to allow dict and list values (#2907)
• c530f85 Update package metadata to comply with PEP 639 (#2926)
• 72ac4a0 Reject booleans in from_timestamp_ms, consistent with from_timestamp (#2904)
• 024b5d0 Fix Enum field by-name lookup to only return actual members (#2902)
• 252090c Fix nested partial to use attr_name instead of data_key for prefix (#2903)
• 65374df Fix OneOf.options() emitting phantom entries when labels outnumber choices (#...
• 070dde0 Fix Constant field with required=True raising ValueError (#2901)
• fea5428 Make Number and Mapping abstract base classes (#2925)
• Additional commits viewable in compare view

• b5acf8b Merge branch 'release-1.42.78'
• 1da17a5 Bumping version to 1.42.78
• e298b64 Add changelog entries from botocore
• 48369ea Merge branch 'release-1.42.77'
• 8c30411 Merge branch 'release-1.42.77' into develop
• 4398c8e Bumping version to 1.42.77
• 7c449e2 Add changelog entries from botocore
• ee6c3e4 Merge branch 'release-1.42.76'
• a5ad9c3 Merge branch 'release-1.42.76' into develop
• 1abf640 Bumping version to 1.42.76
• Additional commits viewable in compare view

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