Are footnotes and endnotes currently possible (besides manually creating them, of course)? I haven't found them so far.
If not, this is a feature that I think would be widely used. I suspect it may take some time to get right if it is not yet under development, so I would understand if it is not a day-1 feature.
Only Serif knows their plans and priorities, and they generally do not announce upcoming changes ahead of time. The new functions just show up one day in a beta release.
We have no idea when they plan to release footnote support. It could still show upi in1.8.x, but might not appear until 1.9 or later.