F - module revision history, Series a versus series b firmware, Corrected anomaly with revision 3.005 and later – Rockwell Automation 1756-IF4FXOF2F ControlLogix High-speed Analog I/O Module User Manual
Page 143: Appendix f, Module revision history, Appendix

Rockwell Automation Publication 1756-UM005B-EN-P - January 2013
143
Appendix
F
Module Revision History
Series A versus
Series B Firmware
If you have a series A module, you can upgrade the module’s firmware to install
the same features that are available on the series B module. Any module that uses
firmware revision 3.005 and later has a series B designator. Series A modules that
are upgraded to revision 3.005 or later also have a series B designator.
Archiving Enhancement with Revision 3.005 and Later
Archiving is provided in firmware revision 3.005 and later. Because it is not
dependent on specialized module hardware, any high-speed analog module can
be updated to perform this function. For more information about this function,
see
Corrected Anomaly with Revision 3.005 and Later
The following anomaly is corrected in firmware revision 3.005 and later.
CORRECTED: When the high-speed analog module, series A, is used in a
system where its connection is through a 1756-EN2T module, I/O connections
cannot complete.
Upgrade the high-speed analog module to series B, firmware revision 3.005, to
enable the proper I/O connection.
Topic
Page
Series A versus Series B Firmware
Series B Modules as Direct Replacements for Series A Modules