Their release notes:
Improvement: new button management (faster and buffered key detection).
Improvement: new event management (previous versions could miss events).
Improvement: reduced power consumption.
Improvement: Table support in Mobipocket files.
Bug fix: large covers in PRC files.
Bug fix: Asian characters are now displayed properly in PRC files.
Bug fix: PDF viewer memory management (to be continued).
Bug fix: TrueType font detection (“Fonts” directory).
Bug fix: various user interface items (to be continued).
Bug fix: detection of MP3 playback frequencies.
New: in the “Library”, a lock symbol is visible when a read-only SD card is inserted.
How to Download
Download the upgrade file by clicking on the "Download" button.
Extract the content of the downloaded zip file.
You should get a file “update_kernel”; this is the firmware upgrade utility.
Copy the file “update_kernel” to the root of an SD card.
How to Install
Make sure your Cybook has enough power to operate.
Switch off your device.
Insert the card into your Cybook.
Switch on your device.
When the boot image is visible (Cybook & Bookeen logotypes), press the “Enter” key and keep it pressed for a few seconds until the screen flashes.
When the screen flashes, you can depress the key; the upgrade process is launched.
Only the needed sections are updated. The upgrade should complete after a couple of minutes.
When the upgrade is completed, the Cybook starts normally.
Delete the file “update_kernel” from the SD card and from your computer. This file will not be useful anymore.
Congratulations! Your Cybook has been upgraded with software version 1.1.
New directory view.
Improved Mobipocket, PDF, HTML & TXT support.
New user interface features.
User interface translations.