If you're curious to know when the first three Halo 4 map packs would be released, Microsoft may've actually announced the exact dates earlier than expected. An ad recently seen on the German Xbox 360 dashboard announced exact dates for the first three packs -- Crimson, Majestic, and Castle.
Microsoft already confirmed last month that the map packs, which are part of the Halo 4 War Games Pass, would be releasing December, February, and April, respectively. According to the foreign ad, the dates are actually December 10 for the Crimson Pack, February 25 for the Majestic Pack, and April 1 for the Castle Pack.
When contacted, Microsoft only conceded that the months were accurate. Their statement reads:
"Halo 4 War Games Map Packs will become available in December, February and April. The exact release dates are pending the production schedule for each map pack, but we look forward to sharing more details in due time."