A number of our clients have received emails like this one below:
The hacker sometimes puts a real-but-old password in the subject line, to really scare the client. It is possible that the client has used that same password somewhere else (with LinkedIn, Facebook, etc.) and those services are occasionally hacked, so that could be how they get the old password.
WHAT TO DO:
If they mention a password, it might be a good idea to change it. After reporting this to us and to bitcoin, you can ignore the message. Let us know if you have any questions.