Sending messages at any time of the day or night is the done thing here and it seems to be acceptable but in Australia, hell no.
You don’t ring someone after about 8pm and you definitely don’t send a message at midnight. In fact people who do are either telling you bad news or it’s a booty call. Or it’s New Year’s Eve. They are the only exceptions.
I’ve fallen into the trap of doing it here too and that means that my sleep is now disturbed.
It’s funny because I had a friend here once complain about my early morning messages and yet she had no problem sending them to me in the middle of the night. Go figure.