A smaller update than 0.4, but you will notice it in every match.
Walls now join up properly when they run diagonally or in a curve. A diagonal wall used to look like a row of loose posts; now it is one wall. Drag straight or at an angle, and hold Ctrl while dragging to place a ring of wall around the point where you started.
Every unit and building now sees in a smooth circle that moves along with it, instead of a block of squares. Enemies fade in and out at the edge of your sight instead of suddenly popping up, and the edge of unexplored land is a smooth line instead of a staircase.
On random maps every start now has a fair amount of forest nearby, also on Plains, where some starts had almost no wood. On Woodland the poorest start gets less extra forest than before.
Playing online? Everyone needs 0.4.1 to play together. If you see "different game version", restart Steam and it will fetch the update.