Favourite Book Reader works on all major operating systems (Linux, macOS, Windows) and mobile platforms (iOS, Android).

FBReader supports both unencrypted books and ePubs protected by Readium LCP DRM.

Key features include:

1. Comfortable reading experience: Fully customizable text styles and colours for day and night modes, advanced navigation tools, and bookmarking.

2. Flexible access to book sources: You can configure a list of network book sources to download both free and paid books. Additionally, you can open local files or add your preferred OPDS catalogues. FBReader offers a robust catalogue browser with browsing history, bookmarks, and search functionality.

3. Seamless cloud integration: FBReader synchronizes your books, reading progress, and bookmarks across all devices. Start a book on your computer and pick up where you left off on your tablet or smartphone.

Supported book formats include ePub (with key features of ePub3), unencrypted Kindle azw3 (also known as Mobipocket), and fb2(.zip). Other supported formats: RTF, DOC (Microsoft Word), HTML, and plain text.