Add descriptive date format
Along with the existing date timestamp options, I think another useful (and friendly on the eyes) option would be "September 23, 2018". This makes it extremely clear when the review was published.
In my case, my website attracts customers from all over the world, so it wouldn't matter which date format I choose - it will confuse somebody. In Australia we use DD/MM/YY, but USA uses MM/DD/YY, so seeing 10/04/18 isn't very clear in this case.