Could someone please clarify the purpose of the new file types in
Excel 2016/365, as I'm confused.

In various web articles/posts, such as this example
http://www.askingbox.com/question/ex...-xlsm-and-xlsb
I read that xlsx does not include macros or VBA code, but xlsm does.

So, as I want to include my old macros fro Excel 2000 and also use any
new macros I might install (with help here!) I have started using
xlsm.

HOWEVER, when I open a few remaining xlsx files that I saved earlier,
I find they *do* include macros. I can run them, and I can open the
VBA Editor.

--
Terry, East Grinstead, UK