need help convert this irule to 9.2.4

You could use an if statement like this:

when HTTP_REQUEST {
  if { [HTTP::host] contains "npg.nature.com" } {
    pool pressandgateway
  } elseif { [HTTP::host] contains "press.nature.com" } {
    pool pressandgateway
  } else {
    discard
  }
}

or... you could go with a switch statement which allows for a logical or by using a "-" terminator on a comparison string.

when HTTP_REQUEST {
  switch -glob [HTTP::host] {
    "*npg.nature.com*" -
    "*press.nature.com*" {
      pool pressandgateway
    }
    default {
      discard
    }
  }
}

Your choice...

-Joe