Calibre, the popular open-source e-book management software, has released version 9.16, introducing more natural text-to-speech voices, improved PDF handling, faster library operations, and expanded support for downloading news from websites.
One main addition is support for Kokoro voices in the Read Aloud feature. According to the developers, these high-quality voices sound more natural than the existing Piper options, especially when reading English text.
Users can access them by selecting the Piper backend in the Read Aloud settings and choosing one of the available Kokoro voices. The required voice files are downloaded automatically the first time they are used.
Another notable improvement is Calibre’s built-in news downloader. Version 9.16 adds support for Camoufox, a browser-based solution that lets Calibre retrieve content from websites blocking conventional automated downloading methods.
This affects news sources like The New York Times, The Economist, and The Atlantic, whose download recipes now use Camoufox. The browser downloads automatically when a compatible recipe runs for the first time. Recipe authors can also enable it by setting browser_type = 'camoufox'.
Regarding PDF handling, Calibre 9.16 adds support for right-to-left text when importing PDFs and improves processing of multi-column pages. It also fixes conversion issues affecting documents with vertical writing and cases where content was lost when generating PDFs from multi-column HTML layouts.
Beyond these changes, Calibre 9.16 includes performance optimizations for users managing large e-book collections. Operations like startup, deleting multiple books, sorting by series, searching, and refreshing the Tag browser are now faster.
The e-book viewer also gains useful options, including displaying the immediate parent table-of-contents section in headers and footers. E-books can store up to 1 MB of persistent data, and the Print to PDF feature now accepts margins in metric units. Another addition is support for reading images in the AVIF format.
For e-book editors, the Check Book tool can now ignore selected problem types and automatically update CSS selectors when fixing invalid IDs. The table-of-contents view also shows which entries belong to the file being edited.
Other changes include searchable rules in the Tag Mapper and HTML/CSS transformation tools, improved sorting of hierarchical tags, a button to reset the main window layout, and support for newer Kobo firmware.
On the bug-fixing side, Calibre 9.16 fixes broken navigation links during EPUB 3 conversions, missing non-breaking spaces in DOCX output, dark-mode rendering conflicts in the e-book viewer, and several interface issues. The built-in content server also receives security hardening fixes.
Lastly, the release adds four news sources, including Poetry Magazine and The Believer, and improves existing recipes for Reuters, Heise, The New York Times, The Atlantic, and others.
For more information, see the official changelog. Calibre 9.16 is available for Linux, Windows, and macOS from the project’s download page.
