GA release 1.3.9

[Radhika Gupta (rads-1996)]

1.3.9 (2026-09-09)

Features Added

• Update OpenTelemetry dependencies to latest versions, bump langchain-core minimum version to address S360, and support the new httpx2 entry point exposed by opentelemetry-instrumentation-httpx.
  (#254)
• Add independent dependency checks for the httpx and httpx2 instrumentation entry points.
  (#259)

[github-actions]

Performance comparison

Threshold: regressions >15.0% on gating scenarios fail the build. Higher ops/s is better; positive Δ means the PR is slower.

Scenario	Gating	Baseline (ops/s)	Candidate (ops/s)	Δ %	Status
azure_monitor_log	yes	24,648.1	24,563.4	+0.35%	✅
azure_monitor_span	yes	162,893.0	163,158.8	-0.16%	✅
otel_log	no	28,031.6	28,063.1	-0.11%	✅
otel_span	no	48,923.7	48,330.2	+1.23%	✅

[Copilot]

🟢 Approval recommended

The changes are limited to consistent version bumps and a straightforward changelog finalization with no behavioral code modifications.

Pull request overview

Prepares the microsoft-opentelemetry Python distro for the 1.3.9 GA release by aligning package version metadata and finalizing the changelog entry/date.

Changes:

• Bump package version to 1.3.9 in both runtime and packaging metadata.
• Mark the 1.3.9 changelog section as released with the release date and finalize the listed items.

File summaries

File	Description
src/microsoft/opentelemetry/_version.py	Updates internal runtime version constant to 1.3.9.
pyproject.toml	Updates project/package version to 1.3.9 for distribution metadata.
CHANGELOG.md	Finalizes the 1.3.9 release section with date and feature bullets.

Review details

• Files reviewed: 3/3 changed files
• Comments generated: 0
• Review effort level: Lite

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