Ion Auth Password Strength Validation
Among options to validate the strength of password is also found this one.
You can change the default settings for Ion Auth password strength validation from config.php.
Digits Required For Password
$config['min_digits_for_password'] = 1;
Lowercase Letters Required For Password
$config['min_lowercase_chars_for_password'] = 1;
Uppercase Letters Required For Password
$config['min_uppercase_chars_for_password'] = 1;
Non-Alphanumeric Characters Required For Password
$config['min_non_alphanumeric_chars_for_password'] = 0;