Mysql 5.7.9 has some additional security features that are at least useful for slamming your head against, if not actually improving your security.

1. There’s a default password set for ‘root’ when first running the server.  The password is not generated as a result of the installation as the documentation claims, but only when the server is actually started.  Don’t go hunting for it until you’ve started the server.
2. There’s a new default password security policy.  The current setting can be viewed with this query:

3. mysql> SHOW VARIABLES LIKE 'validate_password%';
   +--------------------------------------+--------+
   | Variable_name                        | Value  |
   +--------------------------------------+--------+
   | validate_password_dictionary_file    |        |
   | validate_password_length             | 8      |
   | validate_password_mixed_case_count   | 1      |
   | validate_password_number_count       | 1      |
   | validate_password_policy             | MEDIUM |
   | validate_password_special_char_count | 1      |
   +--------------------------------------+--------+