I've updated the library (Phidgets22) to 1.14 and then updated the firmware on a HUB5000_0 from 203 to 204.
In the Phidget Control Panel, on any digital input (or output) channel, the data is very unstable and the popup data window flashes the data (attached, Version, Serial Number, hub port, data state) on then off rapidly. Same for all channels but the Voltage Input/Output window "seems" stable. Although I've not tested them with any connected devices.
I had a few issues trying to downgrade to 203 (kept telling me I had something else connected). I pulled the power and tried again and eventually downgraded to 203. Seems to be working fine on 203.
Looks like there are some issue with 204 and wouldn't recommend upgrading until they have been resolved.