I have posted this note in the hope it will save other users spending hours wondering why the Pause/Resume control OSC messages targetted at remote enabled rundowns do not work in the SVT default client.
The code required to add the recognition of the /control/pause osc message has been missed out of source file RundownTreeWidget.cpp. The issue is present on clients 2.0.8, 2.0.9 and 2.2 on Windows, MacOS and Linux.
The details are in issue report number 304 on Github CasparCG Client repository. here.