Unless you very recently purchased your Canon EF 40mm f/2.8 STM Lens
, the answer to this question is probably "Yes". But, Canon Japan has published a serial number key to reliably determine that your EF 40m STM Lens needs the v1.2.0 Firmware Update
If the third digit in the serial number is a 0, 1 or 2, the firmware update is needed:
xx0xxxxxxx, xx1xxxxxxx, xx2xxxxxxx
Otherwise, firmware version 1.2.0 or later has already been installed in the lens.