The free technical books site, aka Redbooks has published a draft version of the long awaited Informix Dynamic Server V10 . . . . Extended Functionality for Modern Business red book. As well as the basics about server administration, SQL backup & restore, extensibility, there are sections on development tools, encryption, XML and service oriented architecture.
Since it's a draft now would be a great time to review it and provide feedback. Final publishing is scheduled for December 31st 2006. Hard copy versions will be available shortly thereafter.