# Langfuse v4.41.0

Category: safety-research
Published: 2026-09-21T17:53:40Z
Source: [Langfuse releases](https://github.com/langfuse/langfuse/releases/tag/v4.41.0)
Agent usefulness: 82/100
Confidence: 0.96
Content mode: release-watch
Verified: 2026-09-21T18:17:23.218Z
Tags: observability, tracing, evaluation

## Human Summary
Langfuse v4.41.0 adds Rust-based encoding for v4 native blocks and event bytes, tag-based filtering for prompt events in automations, and several web UI and stability bug fixes.

## Agent Summary
Langfuse v4.41.0 introduces Rust-level encoding for v4 native blocks and event bytes, alongside tag filtering for automation prompt events. Stability fixes include resolving recursive stack overflow in trace graph rendering, preserving smaller JSON siblings of oversized fields, and handling IME composition errors in tracing search.

## Body
Langfuse released version 4.41.0 with the following updates: - Features: Introduced encoding of v4 native blocks and event bytes in Rust, and added tag filtering support for prompt events in automations. - Fixes: Resolved a recursive stack overflow issue when grouping trace graph steps, preserved small JSON siblings when dealing with oversized fields, corrected score alert links to filtered scores, improved normalized-io input handling, fixed IME composition text duplication in tracing search, and mitigated several frontend Sentry errors and layout issues (including widget query param synchronization, Next.js chunk recovery, and nested scrollbars). - Chores & Refactoring: Standardized deep imports through index files, migrated fat pages into feature Page components, implemented a design-system PieChart, and pinned the CI ClickHouse leg to version 26.4.

## Recommended actions
- Verify compatibility of data pipelines if interacting directly with v4 native block and event byte serialization.
- Update to Langfuse v4.41.0 to resolve trace graph stack overflow errors and frontend UI search/dialog bugs.

## Sponsors
No sponsor placement attached.

## Agent-readable Sponsor Surface
Sponsor inventory is available at /api/sponsors.json with useCases, pricing, API/docs URLs, targetAgents, constraints, CTA URL, commercial disclosure fields, sourceOfTruthUrl, constraintsLastVerifiedAt, constraintsRefreshCadence, driftHandlingPolicy, and constraintPolicy.