Fortigate 5.4 standalone management port routing problem

hi everyone

i upgraded fortigate to 5.4. but i can not access to forti with management port

my config

  edit "mgmt1"         set vdom "root"         set ip         set allowaccess ping https ssh http         set vlanforward enable         set type physical         set dedicated-to management         set snmp-index 1

FW# config system dedicated-mgmt command parse error before 'dedicated-mgmt' Command fail. Return code 1 FW # config system dedicated-mgm1 command parse error before 'dedicated-mgm1' Command fail. Return code 1

i cont not see config system dedicated-mgmt in cli.

how can i resolve it?

thanks