Firmware Version 1.3.1 incorporates the following fixes and enhancements:
1. Adds [IPB (Light)] to 4K to enable lower bit rate shooting.
2. Adds [Electronic full-time MF] to the AF tab of the menu. When a lens is attached, manual focus adjustment is always possible with both One-shot AF and Servo AF.
3. The transfer time (estimated value) now displays on the camera monitor during FTP transfer.
4. Fixes a phenomenon, in which in rare instances, the camera cannot function normally when the drive mode is set to "High-speed continuous shooting" to shoot still images continuously.
5. Fixes a phenomenon that may corrupt the image displayed in the viewfinder.
6. Fixes a phenomenon in which the power may become suspended when the camera is powered via USB for an extended period of time.
7. Fixes a phenomenon, in which the camera stops to operate normally when the movie cropping setting is set to [Enable] for performing movie shooting in Firmware Version 1.3.0.