LuaTeX 1.07.0 is now available in the MiKTeX distribution. It comes in two variants:
If you are a script developer, you might want to give the 5.3 engine, also known as luatex53, a try.
Switching the engines is very easy. It only requires two
initexmf --set-config-value [luatex]luaver=5.3 initexmf --force --mklinks
See this HOWTO, for details.