You can check the detailed release history in HelpNDoc's what's new page.

New FTP(S) and SFTP build actions

HelpNDoc 9 introduces new FTP-related build actions, allowing users to directly upload their generated documentation files to FTP(S) and SFTP servers. This feature streamlines the process of distributing and publishing documentation by enabling automated, secure file transfers to web hosts or other online platforms supporting these protocols. See: Build actions 

Library items overrides: Customize them for each build individually

HelpNDoc now allows users to override all types of library items (such as pictures, documents, equations, variables, snippets...) for each individual build. This enables the creation of an unlimited number of variations of the main documentation project. See: Override library items 

New library item type: Dynamic content

Create scripts that dynamically generate HTML-based content, which can be seamlessly integrated within the topics of your project. These scripts have access to the full suite of HelpNDoc's API methods to produce dynamic content. See: Dynamic content library item 

Completely rewritten HTML importer

The enhanced HTML importer in HelpNDoc is now quicker and more dependable, offering better support for modern HTML and CSS features. This improvement ensures a smoother, more accurate import of web content into HelpNDoc projects, facilitating easier integration and better formatting consistency. See: Import other formats 

Greatly improved PDF generator

The updated HelpNDoc PDF generator now produces smaller PDF files with optimized font embedding settings, and handles symbol fonts more effectively. Other PDF improvements include enhanced drawing accuracy for various elements and a fix for over-sized images, ensuring better layout and visual quality.

Improved generation of HTML-based documentation formats

HelpNDoc 9 includes improved HTML/CSS generation for better modern style support and fixes issues with exporting bullets with font symbols to HTML formats. It also enhances HTML code clarity for ePub and Kindle eBooks, reducing validation errors and ensuring smoother compatibility.

Some other improvements and bug fixes

Many bugs are fixed with each release as indicated in the "What's new" page. Some of them include: