Oldname

This command causes GAMS to only allow 10 character set element names for compatibility with systems that do not accept longer names (notably older versions of MPSGE).  It causes GAMS to check that names are less than 10 characters and uppercases the names.

OLDNAME=1

When names are too long a compilation error arises.  There is also an oldname option.  Note it does not require less than 10 character set, parameter, variable etc names and may still not work with older versions.