PD not Current/received case update notice/ADIT

我的PD還有5周才current, 但是今天早上收到USCIS的update:

On February 24, 2015, we registered your permanent resident status and mailed you a Welcome Notice for Receipt Number SRCxxxxxxxxxx. Please follow the instructions in the notice. Your new permanent resident card should arrive by April 25, 2015, after this registration or after you complete any ADIT processing referred to in the welcome notice, whichever is later. 


這是出了問題, 還是工作進度加快了? ADIT processing是什麽?

多謝多謝多謝