Core automatic upgrade feature was introduced in WordPress Version 2.7. While doing automatic upgrade WordPress places a file named .maintenance in your website’s root directory.
The file is shown during automatic and manual updates made from WordPress admin section. But sometimes when WordPress fail in completing the update process (especially when your PHP memory is hitting its resources or during some communication error etc), it keeps showing, “Briefly unavailable for scheduled maintenance. Check back in a minute.” message on every page of your website.
Continue reading How To Clear “Briefly Unavailable For Scheduled Maintenance” Message In WordPress?