SAS/IML 13.1 includes the following enhancements to the syntax:
The NEXT keyword now supports expressions, as shown in the section Process a Range of Observations. This change affects the DELETE, FIND, LIST, READ, and REPLACE statements.
The STOP and ABORT statements now accept a default message that is displayed in the SAS log.
The parentheses in the RETURN statement are now optional.
In addition, the order of resolution has changed for SAS/IML user-defined functions and subroutines. You can now define a function or subroutine that has the same name as a built-in SAS/IML function or subroutine. For more information, see Order of Resolution for Functions and Subroutines.