/correction
Settings regarding Last Message Correction (XEP-0308). Corrections will only work in MUC and regular chat windows. MUC PMs won’t be allowed. For more information on how to correct messages, see: /help correct.
/correction <on>|<off>
/correction char <char>
on|off
Enable/Disable support for last message correction.
char
Set character that will prefix corrected messages. Default: ’+’.