When using the CSSMTP driver email attachments with extension >TXT are limited to record length 998.
An error is seeing in the CSSMTP log if the LRECL is bigger that this limit:
CSSMTP EVENT :026:mlJesReport:Report: 500 5.2.5 JES Text line too long
Release : 14.0
LT08103 allows the driver CSSMTP to send files with larger LRECLs.
This fix is in test status. This knowledge document will be updated with the solution when it is published.