Strangely it isn't announced anywhere, but there it is:
Latest K-m Firmware Update : Software Downloads : PENTAX Changes to V1.10
The following function have been added on Version 1.10
- Added selection of area (Square) to Cropping in the Playback-1 menu
- When Digital Filter is assigned to the Help button in the [Rec.Mode 3] menu, Digital filter can be set by pressing Help button in playback mode.
- Added [Custom] to Digital filter in Capture mode. Digital filter can be customized and saved a filter to your own preferences.