For those of you who live in Europe, the X series of axes from Fiskars is already a common sight. In the US however, they have not been available, until now. The X series is just the newer version of the existing Fiskars axes, with modifications made accordingly. For a look at the axes currently available in the US, you can take a look at my review of the Fiskars 7850 Hatchet.
Some of the changes to the new models include a new handle material-FiberComp and what is reported as an alteration to the grind, to prevent chipping. It also appears that the weight of some of the models has been increased. For example, the X7 hatchet, which will replace the 7850 hatchet, has a head weight that is at least a quarter of a pound heavier than its predecessor.
Currently the older models are being phased out in the US. The company is burning through the stock, and replacing it with the X series. The availability of the new axes will depend on how quickly your local store can sell out the older models, so availability will vary from area to area.