The Apache OpenNLP team is pleased to announce the release of Apache OpenNLP 2.5.8.
The Apache OpenNLP library is a machine learning based toolkit for the processing of natural language text.
It supports the most common NLP tasks, such as tokenization, sentence segmentation, part-of-speech tagging, named entity extraction, chunking, parsing, and coreference resolution.
Apache OpenNLP 2.5.8 binary and source distributions are available for download from our download page.
The OpenNLP library is distributed by Maven Central as well. See the Maven dependency page for more details.
Summary:
Bug Fixes:
The SentenceDetector got three fixes in handling edge cases with abbreviation dictionaries (OPENNLP-1809, OPENNLP-1810, OPENNLP-1811) - NOTE: These fixes have been back-ported to OpenNLP 2.5.8.
Improvements:
The OpenNLP developer manual (HTML + PDF) got an uplift for the UIMA documentation part, being largely extended (OPENNLP-49)
Some updates of dependencies
For further details, check the full list of changes via the project’s issue tracker.
--The Apache OpenNLP Team
31 March 2026