How can you tell what version of MailStream Plus is being used?

One way is that when a job has been ran, the first line of the RPT and XLG output reports give the version number.
The intial text on the line will vary, but there will be something like this in the line-
which means version 8.3.1

Version 8.3.0 would have "R08.3M00"

The internal Cobol names for the files are MSRPRPT and MSRPXLG.

---On Windows and UNIX/Linux platforms, they will normally be files with the jobname and .rpt or .xlg extensions.  Although the output name/location can be customized.  If so, look for the DD for MSRPRPT or MSRPXLG in your script to determine the output name and location.
---On z/OS, look in the DD MSRPRPT or DD MSRPXLG output files.
---On IBMi, look in the PRNTRPT or PRNTXLG spool files.
UPDATED:  April 18, 2017