Error when using 11g export client on a 10g database

The only reason to read this post is if you have googled for the error "ORA-00904: "POLTYP": invalid identifier". This error occurs if you try the old export command from an 11g client against a database on version 10g or lower. The export command runs a query against a table called EXU9RLS in the SYS schema. On 11g this table was expanded with the column POLTYP and the export command (exp) expects to find this column. This should not be much of a problem since Data Pump export can be used.