Calibre 9.16 brings a useful collection of improvements to the popular open-source e-book manager, including more natural text-to-speech voices, better PDF handling, AVIF image support, and performance optimizations for large digital libraries.
Calibre 9.16
Better Read Aloud voices, improved PDF processing, AVIF support, and faster e-book library operations.
Calibre is an open-source application for organizing, converting, editing, and reading e-books. Its built-in tools also support downloading online news and managing digital book collections. Version 9.16 expands several of these capabilities while fixing issues affecting conversions, the viewer, and the content server.
Key Takeaways
- Kokoro voices: New voice options are available through the Read Aloud feature using the Piper backend.
- PDF improvements: Better handling of right-to-left text, multi-column pages, and selected conversion problems.
- Camoufox support: The news downloader can use a browser-based approach for compatible recipes.
- Faster libraries: Several operations involving large book collections have been optimized.
- More format and editor updates: Calibre adds AVIF image support alongside improvements to its viewer, editor, conversion tools, and Kobo support.
What’s New in Calibre 9.16?
01. Kokoro Text-to-Speech Voices
Calibre adds Kokoro voice options to Read Aloud. The voices are designed to sound more natural than existing Piper options, particularly for English text.
02. Better PDF Handling
PDF import gains right-to-left text support and improved multi-column processing. The release also addresses selected PDF conversion issues involving vertical writing and multi-column HTML layouts.
03. Camoufox for News Downloads
Compatible news recipes can use Camoufox to retrieve content from websites that block conventional automated downloading methods. Its browser files are downloaded when first required.
04. AVIF Image Support
The e-book viewer gains support for reading AVIF images, extending the image formats it can handle.
1. More Natural Read Aloud Voices
One of the most noticeable additions in Calibre 9.16 is support for Kokoro voices in the Read Aloud feature. This gives users additional text-to-speech choices when listening to their books instead of reading on screen.
To try the new voices, open Calibre’s Read Aloud settings, select the Piper backend, and choose an available Kokoro voice. Required voice files are downloaded automatically the first time they are used.
2. PDF Import and Conversion Improvements
Calibre 9.16 improves PDF handling for documents with different text directions and complex page layouts. These changes are particularly relevant when working with multilingual documents or PDFs that arrange text in multiple columns.
- Support for right-to-left text when importing PDFs.
- Improved processing of multi-column PDF pages.
- Fixes for selected documents containing vertical writing.
- A fix for content loss when generating PDFs from multi-column HTML layouts.
These changes target specific import and conversion scenarios. They should not be interpreted as a guarantee that every complicated PDF will convert perfectly; always review the output of important documents.
3. Improved News Downloading with Camoufox
Calibre’s built-in news downloader gains support for Camoufox, a browser-based solution that can help compatible recipes retrieve pages that resist conventional automated downloading.
According to the release report, recipes for sources including The New York Times, The Economist, and The Atlantic now use Camoufox. The browser is downloaded automatically when a compatible recipe needs it for the first time.
Recipe authors can also configure the browser choice using the
browser_type = 'camoufox' setting.
4. Faster Management of Large E-Book Libraries
Users with extensive collections may benefit from performance optimizations across several common tasks. Calibre 9.16 improves operations such as:
- Application startup.
- Deleting multiple books.
- Sorting books by series.
- Searching within the library.
- Refreshing the Tag browser.
The release notes describe these as performance improvements; no universal percentage speed increase is specified here. Actual results will depend on library size, storage, and hardware.
5. E-Book Viewer and Editor Updates
The viewer and editing tools also receive several quality-of-life changes. These updates cover navigation, stored data, printing, book validation, and editor workflows.
| Area | Update |
|---|---|
| E-book viewer | Option to show the immediate parent table-of-contents section in headers and footers. |
| Persistent data | E-books can store up to 1 MB of persistent data. |
| Print to PDF | Margins can be entered in metric units. |
| Check Book | Selected problem types can be ignored, and CSS selectors can be updated automatically when fixing invalid IDs. |
| Table of contents | The editor identifies which entries belong to the file currently being edited. |
| Tag Mapper and transformations | Rules are searchable in the Tag Mapper and HTML/CSS transformation tools. |
6. Additional Fixes and Compatibility Updates
Calibre 9.16 includes fixes for several problems affecting conversions and everyday use, including:
- Broken navigation links during EPUB 3 conversions.
- Missing non-breaking spaces in DOCX output.
- Dark-mode rendering conflicts in the e-book viewer.
- Various interface and usability issues.
- Security hardening in the built-in content server.
- Improved support for newer Kobo firmware.
- Better sorting of hierarchical tags and a main-window layout reset option.
The release also updates built-in news recipes, including Reuters, Heise, The New York Times, The Atlantic, and others, and adds four news sources, including Poetry Magazine and The Believer.
Calibre 9.16: Feature Summary
| Feature area | What changes | Who may benefit |
|---|---|---|
| Read Aloud | Kokoro voice options | Listeners and accessibility users |
| PDF handling | Text direction and layout fixes | Users importing or converting PDFs |
| News downloader | Camoufox support in compatible recipes | Users downloading supported news sources |
| Library management | Optimizations for common operations | Users with large collections |
| Viewer and editor | Navigation, format, and workflow fixes | Readers and e-book editors |
How to Get Calibre 9.16
Calibre 9.16 is available for Linux, Windows, and macOS according to the release report. Use the project’s official download page to select the package and installation instructions for your operating system.
Download Calibre
Visit the official project website for platform-specific downloads, installation instructions, and release information.
Visit Official Download PageBefore upgrading
- Back up your Calibre library before performing major maintenance or migration work.
- Use the package or installation method appropriate for your operating system.
- After upgrading, test important PDF conversions and any news recipes you depend on.
Frequently Asked Questions
What is new in Calibre 9.16?
The update introduces Kokoro text-to-speech voices, improved PDF handling, Camoufox support for compatible news recipes, AVIF image support, performance optimizations, and several viewer, editor, and bug-fix updates.
How do I enable Kokoro voices in Calibre?
Open the Read Aloud settings, select the Piper backend, and choose an available Kokoro voice. Required voice files are downloaded when first needed.
Does Calibre 9.16 improve PDF conversion?
Yes. It includes improvements for right-to-left text and multi-column PDF processing, along with fixes for selected vertical-writing and multi-column HTML-to-PDF scenarios.
Is Calibre 9.16 available for Linux?
Yes. The release report lists Linux, Windows, and macOS. Consult the official download page for the appropriate installation method.
Is Calibre free and open source?
Calibre is an open-source e-book management application. Consult the official project website for licensing details, downloads, and documentation.
Final Verdict
Calibre 9.16 is a practical update for readers, e-book collectors, and users who rely on document conversion. The Kokoro voice options expand Read Aloud, while PDF fixes, library performance work, and editor improvements address several everyday tasks.
Users who depend on PDF imports, text-to-speech, or news downloading have the clearest reasons to review this release. Before upgrading a production or heavily customized setup, check the official release information and test your own workflows.
References & Sources
- Linuxiac — Calibre 9.16 E-Book Manager Adds Kokoro Voices, Improves PDF Support
- Calibre Official Website — Downloads
- Calibre Official Website — What’s New
This article summarizes the reported release changes and links to the project’s official resources. Feature availability and behavior may vary by operating system, package, and configuration.