PHP and Micro-services

Most PHP based applications are large and self contained, i.e they are built in a monolithic style. As an example a typical food take-out website built using PHP will typically contain an order module, payment module, contact  module e.t.c.., the problem with this sort of approach is that if for example the order module requires an additional email to be sent out to the delivery staffs that a new order has been made and transportation might be required within the hour, then adding such a feature to the order module will require us to redeploy the whole website while we only added some feature to just one module.