I've found some old discussions saying that annotation layers are not supported by Runtime 10.2, but that there were plans to support it in future releases. However, I cannot find any information about support in 100.2.
As an example, the following layer does not appear for us in the Runtime control: Layer: Addresses (ID: 1)
If annotation layers are not supported, is there a workaround, either in the app or on the server? I am able to create a renderer in the app, and see the features; I just don't have the correct text.
Support for annotation layers within feature services is on the roadmap. We have a team actively working on adding support for this in ArcGIS Runtime and we hope to be able to include this functionality in a release in 2019.
Support for Annotation is available in the new v100.5 release of ArcGIS Runtime SDK for .NET (Layer types described—ArcGIS Runtime SDK for .NET | ArcGIS for Developers) and Pro 2.3 (What's new in ArcGIS Pro 2.3).