I’ve had my Metabones IV for my Sony A6000 for a couple of months now and they do update the firmware quite a lot. The following is the summary of the latest Firmware (V0.40) including the the side button control.
Name: Firmware update V0.40 for EF-E Smart AdapterTM MARK IV
Release date: 3 Feb 2015
Benefits and improvements:
In “Green” mode, wide open button on adapter serves double-duty as assignable “Focus hold” button found on Sony G series lenses. You may for example assign “Aperture Preview” to the the “Focus Hold” button on A7II and get the same DOF preview function as on a Canon DSLR. Image Stabilization ON/OFF status is displayed on A7II as the SteadyShot icon.
- Adds support for Sony A7s silent shutter mode.
- Fixed Sony A7s intermittent startup issue.
- More detailed EXIF data.
- Reliability improvements with some Sigma and Tamron lenses.
- Fixed distance display (in Advanced mode) on VG, FS and A7 series.
- Fixed EF70-200/2.8L IS II USM’s IS on/off switch intermittently inoperative issue.
- Fixed issue of EF40/2.8 STM being wrongly identified as an OSS lens.
- Fixed NEX-5N becoming unresponsive issue when movie capture started