Compile issue with UE4 4.20

[btwolfe]

I realize that this plugin is deprecated, but wanted to leverage some of code that pulls in a URDF and builds the static mesh component tree for a kinematic chain. While building the code, I get the error

Plugins\URoboSim\Source\URoboSim\Private\RFactoryRURDFData.cpp(268): error C2248: 'UFactory::FactoryCreateBinary': cannot access protected member declared in class 'UFactory'

which tells me that the UFactory::FactoryCreateBinary method is trying to access a protected method of UFbxFactory. Not really sure why this is because UFactory is derived from the UE4 UFbxFactory class. Do you know of any changes between UE4 4.18 and 4.20 that makes this not compile now?