How do you get KUDU to use MSBuild 15

Question

Microsoft.Net.Compilers is only supported on MSBuild v15.0 and above

whatever the auto detect tooling is for KUDU, it always selects 14

is

Answer 1

Add an app-setting for your Web App:

MSBUILD_PATH with the value %MSBUILD_15_DIR%\msbuild.exe

This will be picked up by the default deploy script.