A new numbering plan was introduced on 3 May 2010. Since then newly assigned landline telephone numbers have a standard length of eleven digits, including the area code. Area codes remained unchanged, variable in length. Exceptions to the eleven-digit rule are the four cities of Berlin, Frankfurt, Hamburg, and Munich, which are the only cities with two-digit area codes and have ten-digit numbers to avoid exceeding the maximum length of eight digits for a subscriber number.[2]