I have X9DAX-IF motherboard with bios date 3/20 and IPMI 1.88. After bios update, system monitor in IPMI no longer shows any temperature or fan speed reading.
As recommended, you should update IPMI firmware to the corresponding revision recommended by the bios revision you like to use. To resolve this issue, please flash IPMI firmware to the latest or corresponding revision then flash bios again with same revision.