When you convert from 10 speed to 11 speed, you install a different axle that shifts the wheel. You need to have the wheel re-dished to center the rim between the dropouts. (For some bizarre reason, for which I do not know the etymology, The term "dishing" is used to describe centering the wheel over the hub.)

The simple explanation is that you need to (or have someone) loosen the spokes on one side and tighten them on the other side to pull the rim over. Then, you re-true it once it is properly centered.