Siemens SIMATIC ET 200SP System Manual page 244

Figure 12-5
● Before installing the firmware update, make sure that the modules are not being used.
● Modules with firmware version V0.0.0 do not support the "firmware update" function.
Note
Firmware update of I/O modules
The L+ supply voltage must be present on the module at the start of and during the firmware
update.
Additional requirement for fail-safe modules
Check the firmware version for fail-safe approval
When using a new firmware version, always check that the version is approved for use in
the module in question.
The attachments of the certificate
(http://support.automation.siemens.com/WW/view/en/49368678/134200) for SIMATIC
Safety specify the firmware version that is approved.
Distributed I/O system
System Manual, 09/2019, A5E03576849-AJ
Selecting the software downloads
WARNING
Maintenance
12.6 Firmware update
243