server_startup('mqtt') undefined subroutine?

Attempting to use mh with a mqtt server. Configured using what limited info I could find.

Startup error on &mqtt::server_startup('mqtt'): Undefined subroutine &mqtt::server_startup called at (eval 454) line 1.
at ./mh line 31.
main::ANON('Undefined subroutine &mqtt::server_startup called at (eval 45...') called at (eval 454) line 1
eval '&mqtt::server_startup('mqtt')
;' called at ./mh line 968
main::setup called at ./mh line 7764