The proper way to update your address is to sign the message containing the new address with your old address. Anybody who acquires your account could post a message saying that they are changing the address, but only the original owner can sign that post with the original address.

Without signing using the old address, here are the possibilities:

1. You are the original owner.
2. You are not the original owner, and you hacked the account.
3. You are not the original owner and you bought the account.