Issue
On the mainframe, the MFS null character, which is used to truncate fields, is defined as being x'3F'. However, in the ASCII character set, this represents the question mark (?) character. Therefore, where an ASCII application uses the question mark character in display data (whether held as literals within the program or obtained from an external source) an alternative null character must be chosen.
Resolution
Enterprise Server allows you to specify at the level of the transaction or the system which character is the null character. The default for this is x'1A'.
You must also edit any programs that use x'3F' to use the new null character instead.