When you import the MakeHuman character, you will notice that the sliders around the face representation are gone. Instead, arm and leg IK are controlled by properties in the MHX drivers panel in the User interface, which is made visible with N-key.
But there are actually quite a few more settings than just the simple FK/IK switches.
The character looks at the Gaze bone, which can move with the head or remain fixed in space.
Move the spine by just using the Shoulders bone, located on the hidden IK Spine layer. Still buggy.
Start the spine from the shoulders rather than from the hips. Should be good for a character walking on his hands or for Spiderman swinging between buildings. The inverted spine bones are located on the Inv FK Spine layer.
Stretchiness of the lower back bones when using spine IK.
Then follow a number of settings that are duplicated for the left and right sides.
If on, the arms do not rotate when the shoulders do.
This is the old switch between FK and IK arms. The arm is controlled by the Wrist bone and the ElbowPT pole target, located on the hidden Arm IK layer.
Arm stretchiness when using Arm IK. A small stretchness is useful to make the hand really stay still. For a large stretchiness, think Elasta girl.
The elbow remains fixed, e.g. when a character sits at a table with elbows on it. The elbow location is at the Elbow bone, current on the hidden Tweak layer. The forearm is controlled with FK or IK depending on the ArmIk setting. Currently buggy.
Whether each finger is controlled by the single bone on the Fingers layer, or the individual bones must be posed separately.
Whether the hand copies the rotation of the IK Wrist bone, or is posed idenpendently.
This is the old switch between FK and IK leg. The leg is controlled by the LegIK bone and the KneePT pole target, located on the hidden Leg IK layer.
Leg stretchiness when using Leg IK.
You will also notice that three more panels have appeared: MHX Lipsync, MHX Expressions and MHX Layers. The pose tool has been built into the MHX importer and will now automatically appear when an MHX rig is active.
Lipsync and expressions will of course only work if face shapes and expressions are exported from MakeHuman, and the Face shapes option is enabled on import.
The Blink/Unblink and pin buttons have some update issues which are currently under investigation. When you press on of these buttons nothing happens in the viewport until the next time a bone or a property slider is moved. The problems can be evaded by e.g. hitting the Blink/Unblink button again, but that is not how it should be.
Everything works with file linking, because the sliders are object properties of the rig.