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MailStream Plus Does the windows application of Mailstream Plus support variable block format?

The information for Variable block apply to the Mainframe application of the software per the information in the MailStream  Plus Reference Guide.

Position 17 is in  the FILE DF
Record Format Define whether the records in this file are fixed-length or variable-length:
F Fixed length with no end of record delimiter, pads with blanks to set record length (byte stream, mainframe fixed blocked and unblocked)
L Line-sequential with delimiter(s) at end of record For Windows: CR-LF, carriage return line feed, 2 bytes For Unix: New line, 1 byte
U Undefined records
Variable length record - For z/OS, 4-byte record 
Default is F for all platforms
UPDATED:  September 15, 2017