TeraStation Pro = TS-**TGL/R5
TeraStation Pro II = TS-H**TGL/R5
** is the capacity.
If you are using TS-H4.0TGL/R5, you are using TeraStation Pro II 4TB model. You should be able to update the firmware to ver.1.33 to use NFS.
Both TeraStations look same, but inside of the box is quite different. So, you shouldn't apply TeraStation Pro II's firmware to TeraStation Pro.