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LightRAG v1.5.5 released 2026-08-06 (post timestamp 2026-08-06 15

2026-08-06 · 15:53 UTC ·@huang_chao4969 ·2 min read

Brief

LightRAG v1.5.5 (Aug 6, 2026) targets production RAG needs with smarter document understanding and stronger reliability. The release adds an optional Smart Heading DOCX parser to restore intended section structures, implements bounded-memory indexing, write-ahead anchors and rollback for consistent recovery, concurrency and isolation improvements, and patches six security issues after 150 merged PRs and 16 new contributors.

Why it matters

LightRAG v1.5.5 released 2026-08-06 (post timestamp 2026-08-06 15:53:53+00:00) after five weeks, merging 150 PRs and adding 16 new contributors.

Key details

  • Smart Heading (optional in the Native DOCX parser) reconstructs messy Word structures by recovering missing headings, reclassifying body text styled as headings, repairing inverted/skipped levels, detecting merged-document boundaries, and reducing noisy long tables of contents to improve chunking.
  • Production hardening: bounded memory (pipeline RSS no longer grows), reliable recovery via write-ahead anchors, chunk logs and scan-based rollback, stronger concurrency (shared storage, key locks for cancellation/dead-process recovery, workspace-level isolation), plus six security advisories fixed (login brute force, password-comparison timing attacks, stored XSS, SSRF bypasses, ReDoS).
Source evidence

🤯 LightRAG v1.5.5 is now live — built to handle messy documents, long-running indexing, and the realities of production RAG.

Five weeks since our last release, we’ve merged 150 PRs and welcomed 16 new contributors. This release focuses on smarter document understanding, production-grade reliability, concurrency, and security.

📄 Smart Heading: Recover the true structure of messy Word documents

Real-world DOCX files rarely have clean heading hierarchies:
- Headings may be missing outline levels
- Body text may accidentally retain heading styles
- Heading levels may be inverted or skipped
- Merged documents may contain conflicting structures

When chunking relies on these unreliable signals, chunks no longer follow semantic boundaries—splitting related context and reducing retrieval quality.

Smart Heading reconstructs the document’s intended structure by:
- Recovering missing section headings
- Reclassifying body text incorrectly styled as headings
- Repairing inverted or skipped heading levels
- Detecting boundaries between merged documents
- Reducing noise from excessively long tables of contents

Smart Heading is available as an optional capability in the Native DOCX parser and must be explicitly enabled.

🔧 Production hardening
- 🧠 Bounded memory — Pipeline RSS no longer grows continuously with workload, enabling stable long-running batch indexing.

  • 🔁 Reliable recovery — Write-ahead anchors, chunk logs, and scan-based rollback restore a consistent state after interruptions.

  • ⚡ Stronger concurrency — Shared storage reduces cross-process RPC, key locks support cancellation and dead-process recovery, and pipelines now provide workspace-level isolation.

  • 🔒 Security fixes — Six security advisories addressed, covering login brute force, password-comparison timing attacks, stored XSS, SSRF bypasses, and ReDoS.

  • 🖥️ Also included
    WebUI server response time and time-to-first-token metrics, a parser capability matrix, graph-rendering and auto-scroll fixes, configurable file suffixes for MinerU and Docling, plus numerous edge-case fixes across parsing, retrieval, storage, and APIs.

A smarter, safer, and more reliable LightRAG for production workloads.

📦 Release: github.com/HKUDS/LightRAG/re…
🔗 GitHub: github.com/HKUDS/LightRAG

Link

Release v1.5.5 · HKUDS/LightRAG

🎉 AddSmart Heading Recognition Feature For Word Document Starting from v1.5.5, LightRAG's built-in DOCX parser introduces the Smart Heading feature -- enabling better section-based chunking eve...
github.com