@andyfragen Most of it happens on the Jetpack side in https://github.com/Automattic/jetpack/tree/trunk/projects/packages/scheduled-updates. When a schedule executes it pings Dotcom to handle the upgrade routine. After some preflight checks in sends an update request back to the site in https://github.com/Automattic/jetpack/blob/trunk/projects/plugins/jetpack/json-endpoints/jetpack/class.jetpack-json-api-plugins-modify-endpoint.php#L384 and follows up with health check, logging, sending out notification emails, etc