Today on a .NET Core 2.1.0 project printing Environment.Version prints out 4.0.30319.42000 which is a hard coded constant in the runtime https://github.com/dotnet/coreclr/blob/ce0a2617d40bc217b8e0a2137e340afe585afcb1/src/System.Private.CoreLib/src/System/Environment.cs#L277. This should print out the actual runtime version based on the policy applied by the host (like 2.1.1 if that's what runtime version is actually being used).

This also needs to be used as the version logged into the event log when there's an unhandled exception reported by the runtime. Today is a bogus version which isn't very useful.