This safety notice was on another forum and I didn't find it here so thought I'd poach their comment and post it:
WARNING: ALL M&P Shield™ firearms manufactured before August 19, 2013.
http://www.smith-wesson.com/webapp/...4_750001_750051_791654_-1_757978_757978_image
WARNING: ALL M&P Shield™ firearms manufactured before August 19, 2013.
http://www.smith-wesson.com/webapp/...4_750001_750051_791654_-1_757978_757978_image