I’ve just tried this and it works:
I’ve installed the latest build and replaced
C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\MSBuild\RemObjects Software\Elements\RemObjects.Elements.Echoes.targets
C:\Program Files (x86)\MSBuild\RemObjects Software\Elements\RemObjects.Elements.Echoes.targets
with a copy of RemObjects.Elements.Echoes.Legacy.targets