March shipping? What? What a joke. I've never understood why products are announced as "available" when they are not available? How could they explain this as "unexpected" demand? What? A product that has not been updated in years. The update announced months ago for December, and when December comes they product is available but wait, no, not really, they don't have enough.
Kind of frustrating, though Apple is not alone on this. Ask Sony where the PS4s are, and Microsoft
where the Xbox Ones are, or Nintendo where the Wiis are a few years back. Intentional or justified, it's just terrible from the customer's perspective.