FYI: This will help with the simple syntax to resolve this issue.
Post Kinetic 2022.1.5 upgrade we are getting the same error. I was reviewing the forum and also had Epicor support ticket. Per developer suggestion, we are able to resolve this issue.
Before:
Erp.Proxy.BO.CompanyImpl _c = WCFServiceSupport.CreateImpl<Erp.Proxy.BO.CompanyImpl>((Ice.Core.Session)oTrans.Session, Epicor.ServiceModel.Channels.ImplBase<Erp.Contracts.CompanySvcContract>.UriPath);
After:
Erp.Proxy.BO.CompanyImpl _c = WCFServiceSupport.CreateImpl<Erp.Proxy.BO.CompanyImpl>((Ice.Core.Session)oTrans.Session, Erp.Proxy.BO.CompanyImpl.UriPath);
on F5-Validate code, no compilation error any more and worked for us.