The lightweight mode brings benefits to sessions connecting to virtual Linux desktops, and Enterprise Desktop does not support virtual Linux desktops. That product is for access to the physical display. What you need is the Workstation. Please read here for more info about lightweight mode: https://www.nomachine.com/AR02L00779.
I suggest you give Workstation a try. It is most likely what you are looking for. On the client side, it is recommended you install the latest NoMachine Enterprise Client or the free NoMachine package to connect to your server in order to take advantage of the features that version 4 has to offer.
I can’t comment on connecting with earlier clients (e.g 3.x or clients which are not our own). The forums deal entirely with version 4. Questions about NX 3 and earlier can be directed via General Enquiries using the Contact Us link in the footer of the website.