IPC-4821 Amendment 1 provides the update of IPC-CF-148 to the correct IPC-4563, references the IPC-TM-650, Method 2.5.7.2 for correct Hi-Pot testing of these thin materials, uses proper reference for visual inspection by inspectors and finally, updated the first five material specification sheets (IPC-4821/1 through IPC-4821/5) that now show Effective Dates of April 2010. The Specification Sheet IPC-4821/6 has not been updated and therefore retains the Effective Date of May 2006.