Episerver/Optimizely Alloy demo site: Microsoft.Owin error

Issue:

After installing the Episerver (now Optimizely) Alloy demo site on startup get the error:

Could not load file or assembly ‘Microsoft.Owin, Version=2.1.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35’ or one of its dependencies. The located assembly’s manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

Solution:

Using the NuGet Package Manager to upgrade Microsoft.Owin to the latest version.