I believe any house currently placed will have received a mail. This is specific to a few Krayt spawn locations, the commit for the update is expanding these particular locations;
{"krayt_big_game_hunt", -1228, -289, {CIRCLE, 256}, NOSPAWNAREA + NOBUILDZONEAREA},
{"krayt_skeleton_1", -6206, 5054, {CIRCLE, 128}, NOSPAWNAREA + NOBUILDZONEAREA},
{"krayt_skeleton_on_hill", -6744, 3568, {CIRCLE, 128}, NOSPAWNAREA + NOBUILDZONEAREA},
The rest of the Krayt statics don't have a change, so I would assume they're okay. So if you have a house at/near those waypoints, check your character mail.
