How to factory reset the Naim unitiserve T2 music server?

How to factory reset the Naim unitiserve T2 music server?
Will it then reset to 1.7a or leave the previously installed 1.7c?!

You can set the UPnP server to defaults. It will not revert to a previous firmware version if you do it.
You can do this in the UPnP Settings menu in the browser interface. Possibly also in the DTC but I don’t use PCs so not sure if that option exists there.