Apache SpamAssassin 4.0 – New Features and Improvements

Apache SpamAssassin is an open‑source spam‑filtering solution that provides system administrators with a scoring framework and a modular plugin architecture to classify and block unwanted bulk email using heuristics, statistical analysis, DNS blacklists, and collaborative filtering databases.

The recently released 4.0 version is a significant update compared with the 3.4 series, bringing many enhancements and new capabilities.

Full Unicode character support and native UTF‑8 handling, enabling effective blocking of spam in multiple languages.

Improved geolocation features.

Enhanced Bayesian filtering, especially for non‑English messages and common words.

Better SSL client‑certificate support.

New plugin to verify email compliance with DMARC policies after parsing DKIM and SPF results.

Plugin that decodes shortened URLs from various URL‑shortening services to reveal the real destination for spam checks.

ExtractText plugin that can invoke external tools to extract text from attachments such as PDFs or Microsoft Office documents, with optional Tesseract OCR for image‑based text.

Various bug fixes and performance optimizations.

The official team states that this version consolidates years of fixes, markedly improves classification accuracy and performance, and has been thoroughly tested in production environments, strongly recommending users upgrade as soon as possible.