I'm getting these errors while building the VST3 only version of the plugin:
\project_source\source\vst_source\customparameters.cpp(41,5): error C2065: 'String': undeclared identifier
\project_source\source\vst_source\customparameters.cpp(41,12): error C2146: syntax error: missing ';' before identifier 'str'
...
\project_source\source\vst_source\customparameters.cpp(52,5): error C2065: 'str': undeclared identifier