Use fsc 4.x to compile your code

build.fsx

//...

let fscToolPath = findToolFolderInSubPath "fsc.exe" "packages"
let msbuildProps = [ "FscToolPath", fscToolPath ]

Target "Build" (fun _ ->
    !! projectFile
    |> MSBuildReleaseExt releaseDir msbuildProps "Build"
    |> Log "AppBuild-Output")

//...

paket.dependencies

group Build
    framework: net462
    content: none
    source https://www.nuget.org/api/v2

    nuget fake
    nuget FSharp.Compiler.Tools