Gmoccapy doesn't start. Reference button?

Hi 
I am setting up a new machine. A simple XYZ Router. No encoders with step/dir on an 7i76ED.

Axis starts but when gmoccapy tries to construct the homing buttons it fails.Found an error!
Error message:
The following information may be useful in troubleshooting:

Traceback (most recent call last):
  File "/usr/bin/gmoccapy", line 5237, in <module>
    app = gmoccapy(sys.argv)
  File "/usr/bin/gmoccapy", line 269, in __init__
    self._make_ref_axis_button()
  File "/usr/bin/gmoccapy", line 664, in _make_ref_axis_button
    btn.set_property("tooltip-text", _("Press to home {0} {1}").format(name_prefix_sg, elem.upper()))
AttributeError: 'int' object has no attribute 'upper'

upper() in python means convert to Upper Case as I understand. 
Never encountered such a problem.
I used the latest ISO for the installation and I am running 2.8.3.

Thanks Andreas     

This error recently popped up but it was unfortunately only fixed in master (LinuxCNC 2.9): github.com/LinuxCNC/linuxcnc/pull/1842
I pushed a fix to 2.8.