Just downloaded via NuGet the .NET SDK (v5.5), refreshed the reference to Dropbox.Api in the projects, and now the .NET projects that successfully used the previous SDK (v4) are now throwing this error when attempting to load the Dropbox.Api reference:
"Could not load file or assembly 'Dropbox.Api, Version=5.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. A strongly-named assembly is required. (Exception from HRESULT: 0x80131044)"