Welcome, @anon88498403,
That’s right, it’s not configurable, but if you hover what’s shown you’ll see the full date info.
Also, it only is done for near-term dates (within a week); dates outside the week show month and date.
It used to be that if you hovered the day you’d see the full date (as in the screenshot in the post below), but that appears gone now. @Vanessa_N, is there any chance that’s a bug? That’s an unfortunate loss.
You can vote for this request if you want, and perhaps find another to vote on or add one:
Thanks,
Larry