This firmware update (Version 1.0.6) incorporates the following enhancement.
Firmware Version 1.0.6 enhances the AF tracking performance.*
*AF performance has been enhances for receding subjects and for subjects that are approaching at a low speed.
Firmware Version 1.0.6 is for cameras with firmware up to version 1.0.4. If the camera’s firmware is already version 1.0.6, it is not necessary to update the firmware. (Please note that there is no Firmware Version 1.0.5.)