How to show headers?

I've been using the "newer" version of Zoho Mail in my browser (Chrome) for a few months, but I've hit a snag which may mean I have to revert to the "older" version. Very occasionally, I have the need to view a message's headers (including most importantly time of arrival), and I can't find a way of doing that using the "newer" version. Before I switch back, can you tell me if I'm missing something?

Regards,

Bob Bevan-Jones