Error: Typescript Feature 1.5. Current language level is 1.4

Question

I am working in the context of Visual Studio 2015 (with Resharper), and am referencing a TypeScript definitions file for NodeJS. I have 3 other VS projects that are using

Answer 1

It's a ReSharper setting. From the menu bar in Visual Studio, click Resharper → Options → Code Editing → TypeScript → Inspections, then change the TypeScript language level to the relevant value.