The iPhone 6 plus with the original Apple case fits after removing a Platikschale in the dock.
But by removing the plastic shell sits the Iphone only on the connector and is thus placed quite shaky.
Unfortunately the dock for the size and length of the iPhone 6 is plus unsuitable, due to the high center of gravity of the iPhone and the low weight tilts the dock around at the slightest breath of wind.
Thus, the Dock is not really usable and goes back.