Apply steps

While a release is Applying, the release page shows Applying to your site with a step list and a count (4 of 10).

Step	What it does
Fetching release	Gets the release's download addresses.
Downloading	Downloads the signed package.
Checking the site	Pre-checks disk space and permissions.
Snapshotting	Saves the current tables and files for rollback, including a WXR export of drifted posts.
Staging database	Restores the release's tables beside the live ones.
Staging files	Places the release's theme, plugin and upload files beside the live ones.
Merging settings	Merges options, keeping site-specific values such as URLs and keys.
Switching over	Swaps staged tables and files into place in one short maintenance window.
Health check	Loads the home page and the REST API and checks the release marker.
Reporting	Sends the health report to Wigoh.

Your site stays up while the release is staged; the switch-over takes a few seconds.

Every file's checksum and the release manifest's signature are verified before anything is staged.