We've temporarily disabled remote inbound connections to MySQL on the P1 server. While this won't impact most websites in any way, any user making use of remote MySQL will now see connection errors or refused connections. If you feel part of your website is impacted, please open a support ticket with details on your website, how remote mysql is being used, and any IPs that need to connect to MySQL remotely.
All other servers and services are not impacted by this change.
August 6: Resolved. See reply below.