Firmware Version 1.0.3 incorporates the following fixes:
Corrects a phenomenon in which when using the camera with the EF-S 18-135mm f/3.5-5.6 IS USM or EF 70-300mm f/4-5.6 IS II USM lens, even if lens aberration correction is set to “Enable”, correction will not be applied.
Firmware Version 1.0.3 is for cameras with firmware up to Version 1.0.2. If the camera's firmware is already Version 1.0.3, it is not necessary to update the firmware.
When updating the firmware of the camera, please review the instructions thoroughly before you download the firmware.