It appears there have been multiple people declaring that the Necron codex (the old one), is no longer on the Games Workshop site for sale. I went and checked the U.S. site, and indeed it was not there. Of course we have seen these types of thing happen, and then a day or two later they re-appear (GW loves playing games with our heads), but if it is gone, is the Necron codex going to arrive much sooner than we are thinking?
Also checked, the Warhammer Fantasy Codex "Ogre Kingdoms" is there. Original rumors had predicted Necrons anywhere from August- October, and finally a set back pushing them to November.
But, But.... "Sisters of Battle is being released in next months White Dwarf". So what. Would a White Dwarf release postpone an actual full codex release. Marketing wise, probably.
So my guess, is that White Dwarf will provide us with some Sisters of Battle next month, possibly even the following month (but we don't know for sure), and then who knows. We could be seeing a earlier release of Necrons than the current rumor mill is thinking. September?