Help please to make clear what does this e-mail mean! About AP!

I received this e-mail from USCIS as below. But I do not understand what does this mean.

Current Status: Document mailed to applicant.

On August 10, 2007 we mailed the document to the address we have on
file. You should receive the new document within 30 days. If you do not,
or if you move before you get it, call customer service.

所有跟帖： 

• 批啦. -玉坠儿- ♀ (0 bytes) () 08/10/2007 postreply 19:54:50

• Really? Why they did not say your card was ordered? -bestwishesgoodluck- ♀ (20 bytes) () 08/10/2007 postreply 20:03:54

• 放心吧.卡就快到啦! -玉坠儿- ♀ (0 bytes) () 08/10/2007 postreply 20:05:53