Error when registering fhir service Microsoft.Health.Fhir.Core.Registration.IFhirServerBuilder

[shuhaibk54]

When I tried to register fhir service I am getting the below error, this is how it's registering into to container .
Microsoft.Health.Fhir.Core.Registration.IFhirServerBuilder fhirServerBuilder = services.AddFhirServer(Configuration);

It was perfectly working fine with hl7 version 1.9.0, now I upgraded all hl7 packages to 4.3.0(latest version )

error when running the application :

Unable to load one or more of the requested types.
Could not load type 'Hl7.Fhir.Model.OperationOutcome' from assembly 'Hl7.Fhir.R4.Core, Version=4.3.0.0, Culture=neutral, PublicKeyToken=d706911480550fc3'.
Could not load type 'Hl7.Fhir.Rest.ResourceFormat' from assembly 'Hl7.Fhir.R4.Core, Version=4.3.0.0, Culture=neutral, PublicKeyToken=d706911480550fc3'.
Could not load type 'Hl7.Fhir.Rest.ResourceFormat' from assembly 'Hl7.Fhir.R4.Core, Version=4.3.0.0, Culture=neutral, PublicKeyToken=d706911480550fc3'.
Could not load type 'Hl7.Fhir.Rest.ResourceFormat' from assembly 'Hl7.Fhir.R4.Core, Version=4.3.0.0, Culture=neutral, PublicKeyToken=d706911480550fc3'.
Could not load type 'Hl7.Fhir.Rest.ResourceFormat' from assembly 'Hl7.Fhir.R4.Core, Version=4.3.0.0, Culture=neutral, PublicKeyToken=d706911480550fc3'.

[brendankowitz]

OperationOutcome exists in https://www.nuget.org/packages/Hl7.Fhir.Support.Poco/, so this first error makes sense. Given that you are going up several major versions in the Hl7.Fhir libraries it does signify there are some breaking API changes that might need to be resolved