Bump to v4.9.0.

differenceBy.js

@@ -33,7 +33,7 @@ define(['./_baseDifference', './_baseFlatten', './_baseIteratee', './isArrayLike
       iteratee = undefined;
     }
     return isArrayLikeObject(array)
-      ? baseDifference(array, baseFlatten(values, 1, true), baseIteratee(iteratee))
+      ? baseDifference(array, baseFlatten(values, 1, isArrayLikeObject, true), baseIteratee(iteratee))
       : [];
   });