According to the company, firmware version 1.02 for the Casio EX-S200 and version 1.01 for the Casio EX-Z800 "Increases speed of review display that appears immediately after shooting an image." Firmware version 1.01 for the Casio EX-Z550 "Fixes problem that causes incorrect image storage when certain operations are performed with the 3:2 image size."
The firmware updates can be downloaded from the Casio USA support website:
Casio EX-S200 V1.02 firmware page
Casio EX-Z550 V1.01 firmware page
Casio EX-Z800 V1.01 firmware page
As usual, please read the installation instructions carefully before installing new firmware.