Changelog

July 10, 2026

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2.73.1

(fix): Make the structured User-Agent (emitted when includePlatformHeaders is enabled) comply with the RFC 7230 token grammar. The runtime token is now dotnet instead of .NET, since a leading dot is not a valid token character (e.g. dotnet/8.0.4). The architecture label is also normalized so the 64-bit x86 aliases (x64, amd64, x86_64) all report as the canonical x86_64.

2.73.0

(feat): Add opt-in support for a structured User-Agent header on generated SDK clients of the form {sdkName}/{sdkVersion} ({os}; {arch}) {runtime}/{runtimeVersion} (e.g. my-sdk/1.2.0 (linux; x64) .NET/8.0.4). The OS, architecture, and runtime version are resolved at runtime via System.Runtime.InteropServices.RuntimeInformation and System.Environment. This is gated behind a new include-platform-headers config option and is disabled by default, so existing generated output is unchanged. When enabled it remains subject to the omit-fern-headers config option.