Is fifth edition! Looking at the picture to the right you can see the 40k essentials page from GW's page this evening. If you will notice, you can no longer purchase the 5th edition rulebook from Games Workshop. It can be that items are no longer available to purchase, but to have an item removed is rather rare. When something is removed it is usually replaced by something new within a month or so. With the Big Rulebook being removed we can see that the edition change should be coming very soon. What will be in there I can't say, but the death knell of 5th edition is official.