"Our team are mainly composed by developers, a group of young people who gathered by reading hobby. Regard providing good Chinese reading service as our duty." [sic] - Duokan Developers
Duokan is an alternative operating system for the Amazon Kindle that adds a significant amount of missing features for the Kindle. It is a must have if you want to read EPUBs, PDFs, comics in ZIP files, and even Chinese and Russian ebooks without the frustrations of conversion.
Nearly every Kindle model can run Duokan. Duokan installs alongside the typical Kindle OS, so you can dual boot to it whenever you want (such as to read the Kindle Store's DRM-protected AZW files, or to use free 3G Whispernet).
Duokan gives you many of the missing features that Kindle competitors offer by default, such as the following:
- Diverse Ebook Format Support: MOBI, TXT, PDF, EPUB, RAR, ZIP/CBZ, JPG, BMP, PNG, GIF, TIFF
- Supports a far greater range of languages and encodings (ex. Simplified and Traditional Chinese, Russian, German, French, etc.)
- Better PDF reader
- Better Internet Browser, which can download ebooks through Wi-Fi
- Customise the number of page turns before fully refreshing
- Better dictionary support
- Fine control of fonts and margins
- Lots of shortcut keys
- Easily organized folders
- Over-the-Air Upgrades
- Potentially longer battery life
Duokan has a few caveats, but not to worry.
Duokan does not delete the typical Kindle OS, so you can dual-boot back as necessary.
- Encrypted DRM AZW files from Amazon's Kindle store cannot be read.
- Wi-Fi Only. Duokan cannot use 3G of any kind, and never will support it.
 Supported Devices
(basically all of them, but a list would be nice)
Only one variant of Duokan exists today, Duokan 2013, which replaced both Duokan 2012 and Duokan Lite with one unified package.
Installation is easy, more info in the page Duokan 2013 Installation.
 Duokan for Android
- Free search engine for global Internet books.
- Nice typography
- Simple and clean UI