• USB charging. The camera has a Micro-USB connector, when connected to the provided power adapter the battery inside the camera will be charged. The charge is rather slow, the manual states it requires about 4 hours for a full charge. Charging with a third-party charger works, but is not recommended by the manual.
• Bluetooth connection. You can configure the Bluetooth connection to remain always active, even when the camera is turned off. You can download photos to your smartphone without turning on the camera and causing the lens to initialize/move (which drains the battery and wears out the flexcable).
• Faster Wi-Fi. Downloading photos over Wi-Fi has improved significantly in speed.

• Cannot save MySet. The menu items to save current settings into MySet 1 to 4 were removed! This is a truly outrageous impairment and Olympus deserves the worst punishment for doing so.
• Cannot configure the Shortcut button function. The function button near the On/Off lever was marked Fn3 on the Mark II model and was highly configurable in its function. Now the button has a fixed function and it brings the appropriate menu for the current mode (e.g. the Super Control Panel).
• Multi Function button no longer exists. In the old model the Fn2 button were associated to the Multi Function, i.e. You could assign a set of functions to this button, select the active one by pressing it and rotating the rear dial, and then activate the coosen function simply by pressing Fn2. Now four fixed functions are associated to the arrow pad: AF target, ISO sensitivity, Flash and Sequential/self-timer shooting.
• Case made of plastic. The upper part of the case was made of aluminium on the Mark II model, not it is in plastic. (: Also the bottom plate?).
• Cannto customize Auto Power Off time. The default 4 hours timeout cannot be changed unlike model Mark II.

The UBS charger provided with the E-M10 Mark IV is rated at 5 V 1.5 A. Although the manual recommends using only the original charger, I think that it is safe to use on rated in the same way.