v4.20.18 v4.21.0

Name: fastmcp
Author: punkpeye

punkpeye/fastmcpSep 25, 2026 → Sep 25, 20260 days between releases

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Analyzing what changed between v4.20.18 and v4.21.0. This page updates automatically — usually within a minute.

The Two Releases

v4.20.18

Sep 25, 2026· 27 days ago

Addresses a specific bug in OpenAPI schema conversion where boolean exclusive bounds from OpenAPI 3.0 were incorrectly transformed into JSON Schema numbers.

Full release notes

v4.21.0

Sep 25, 2026· 27 days ago

This release introduces support for the `iss` (issuer) claim in authorization responses according to RFC 9207. It also includes a bug fix to ensure record value schemas are correctly advertised in tool inputs.

Full release notes