Here's another part to that mail that you might have missed:

Physical product should arrive in our Digital River warehouses in the US and the UK within five to seven business days. Orders for physical product will start being processed at that time, and all orders should ship within one to two business days. The timing for receipt of individual orders will then be based on the delivery method chosen when preordered.

Basically, all boxed orders are going to start shipping 5 to 7 days after the 21st.