I changed my Facebook password a few days ago. Today, I entered the old password chronically, and saw this message:

> 
> Sorry! You entered an old password
> 
> 
> 

And even shows the date and time when I changed the password. What's more if it will tell me if I changed the password on the same network.

Indeed, this is a user-friendly prompt for those who forgot changing the password. But if hackers want to invade one's account, they could use *social engineering* and other methods to get one's information and then control the account. My question is:

* Would this give away some personal information or, even worse, made use by hackers? Is it proper?
* Is it better to send an email to the user?

Use the same network:
![Use the same network](https://i.stack.imgur.com/A06NB.png)

Use a Japan VPN:
![Use a Japan VPN](https://i.stack.imgur.com/Bihhy.png)