emqx4.3/rel/config/examples/delayed.conf.example

##--------------------------------------------------------------------
## Delayed publish
##
## Configuring the delayed publish feature
##--------------------------------------------------------------------
## Note: This is an example of how to configure this feature
##       you should copy and paste the below data into the emqx.conf for working

delayed {
    enable = true ## false for disabled

    ## Maximum number of delayed messages
    ## Default: 0 (0 is no limit)
    max_delayed_messages = 0
}