Just to let you know, I Went to : Metronic Downloads page (even in the page it still says 8.1.5)
After clicking on download Metronic 8 HTML demo1 card,
It is started to download 8.1.5 not 8.1.6 ?!
Thank you for your feedback.
Now you should be able to download Metronic v8.1.6. Please retry it right away.