No details on contents here, (that will come soon enough) but timeframes are said to be:
Sisters of Battle in July-August timeframe (in White Dwarf, same as Blood Angels were)
Necrons in the October-November pre holiday timeslot (same slot as Dark Eldar were)
And in another “Mystery Box” situation like Space Hulk was, a special something is apparantly coming in October from GW (may be 40k related – maybe not).
~Standard caveats on this stuff. Still, this fits the overall pattern we’re been hearing about for months now, and would give us three 40K codices this year.