FSharp.Core: Could not load file or assembly

Question

I have the following error when attempting to run a test:

{System.IO.FileLoadException: Could not load file or assembly 'FSharp.Core, Version=3.3.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040) File name: 'FSharp.Core, Version=3.3.1.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' at Register.RegisterResponse.__DebugDisplay()

Tests.dll

FSharp.Core: 3.1.2.5

Target F# runtime: 4.3.1.0

Target Framework: 4.6

Output type: Class Library

ManageAccount.dll

FSharp.Core: 3.1.2.5

Target F# runtime: 3.3.1.0

Target Framework: .NET Portable Subset (.Net Framework 4.5, ASP.Net Core 1.0, Windows 8)

Output type: Class Library

I then added the following app config to my test project:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="FSharp.Core" publicKeyToken="b03f5f7f11d50a3a"
                          culture="neutral"/>
        <bindingRedirect oldVersion="3.1.2.5" newVersion="3.3.1.0"/>
      </dependentAssembly>
    </assemblyBinding>
  </runtime>
</configuration>

If I do need an app config, what value should my bindingRedirect be set to?