Firmware information page can be found here:
http://www.paulcbuff.com/fw-e640.php From Version 30:
Corrects the displayed flash duration values for the settings from -2f to -2.9f while in action mode.
Values are communicated to the Cyber Commander from the E640, therefore no update is necessary for the Cyber Commander.
From Version 29:
Allows the fan to be controlled by the internal temperatures of the light. The fan will run at slower speeds at cooler temperatures and higher speeds as the light warms up.
From Version 26:
Updates E640 internal component drivers to latest versions.
Users will not notice any changes in performance or features from firmware version 26.
From Version 22:
Updates E640 for compatibility with Pocket Wizard Power MC2 remote
With the Cyber Commander™, when the Einstein™ is not in a selected group, the new firmware turns off its modeling lamp and disables the sync jack and slave eye
From Version 20:
Increases the Pump Temperature reading at which the light shuts off from 60°C to 105°C, increasing the time before thermal shutdown.
Includes a cosmetic change to the diagnostics screen.
From Version 19:
Corrects an issue where the light may double fire when a triggering cord is connected in the 1/8” sync jack.