Log Message:
Update postfix to 3.1.3.

Fixed with Postfix 3.1.3 and 3.0.7:

  * The Postfix SMTP server did not reset a previous session's
    failed/total command counts before rejecting a client that
    exceeds request or concurrency rates. This resulted in incorrect
    failed/total command counts being logged at the end of the
    rejected session.

  * The unionmap multi-table interface did not propagate table
    lookup errors, resulting in false "user unknown" responses.

  * The documentation was updated with a workaround for false "not
    found" errors with MySQL map queries that contain UTF8-encoded
    text. The workaround is to specify "option_group = client" in
    Postfix MySQL configuration files. This will be the default
    setting with Postfix 3.2 and later.