Changelog

Version history and release notes.

v16.6.5

Added SSL certificate expiry monitoring. Receive email or Slack alerts before a certificate expires — 7 days before on Free, or on multiple custom thresholds on Pro.
Added redirect monitoring. Each check now verifies that the URL redirects to the expected destination or upgrades from http to https. A failed redirect triggers a downtime alert.
Fixed a bug where WP-Cron events were not removed when uninstalling the plugin with the "keep data" option enabled.

Added redirect destination display to manual check results. When a URL redirects to a different address, the final destination URL is now shown in the result card on the Diagnostics page — making it easier to spot unintended redirects, domain migrations, or login-page forwarding.

Added failure reason classification. When a monitor goes down, the plugin automatically identifies and displays the cause — such as DNS failure, timeout, SSL certificate expiry, SSL error, connection error, HTTP 5xx, HTTP 4xx, keyword mismatch, or slow response. The reason is shown as a badge in the monitor list and included in email and Slack notifications.
Added a plugin health check panel to the Diagnostics page. You can now verify that WP-Cron is enabled, check whether the monitoring event is registered, view the next scheduled run time and the last run time, and inspect the lock status — all from one place.
Added Spanish and German translations. The admin interface, email and Slack notifications, and the WordPress.org readme are now available in Spanish and German in addition to Japanese.

Added re-notification: if a site stays down, an alert is sent again after a set interval (default: 1 hour). You can choose from 5 minutes to 24 hours, or disable re-notification to receive only one alert per incident.
Added "Max Response Time" setting: specify the maximum acceptable response time. If responses exceed the threshold on consecutive checks, a downtime alert is sent — even if the HTTP status is 200 OK. Free plan offers preset options (3–60 seconds); Pro plan allows custom input (1–60 seconds).

Added maintenance window management. You can now register scheduled maintenance periods (one-time, weekly, or monthly), and downtime / recovery notifications will be automatically suppressed during those windows. URL checks and status recording continue as normal.
Improved false-positive reduction. When a check fails and the monitor has not yet reached the consecutive-failure threshold, a re-check is automatically scheduled 60 seconds later. This significantly reduces alert noise caused by temporary network hiccups.
Added a "Recent Failures" column to the monitor list. Even when the current status is Up, you can now see how many checks have recently failed — making it easier to spot intermittent downtime before it becomes a larger issue.

Added keyword check for URL monitors. You can now verify that a specific keyword is present (or absent) in the response body — useful for detecting errors that return HTTP 200, such as maintenance pages.
Added support for multiple notification recipients (Pro). You can now send downtime and recovery alerts to up to 5 email addresses simultaneously. Free plan supports 1 recipient.
Added a "Compare Plans" page to the admin dashboard, showing a side-by-side feature comparison of all available plans.
Improved database migration reliability. Version numbers are now updated only after each migration step succeeds, preventing stuck states on failed upgrades.

Added a monitor history page. Click the "History" button next to each monitor to view recent Up/Down check results, including the checked time, HTTP status code, response time, and any error messages.
Added plan-based history retention periods.
Added site name and site URL to downtime and recovery notification emails, making it easy to identify which site triggered the alert when managing multiple sites.

Added an upgrade page to the admin dashboard. You can now upgrade to the Pro version directly from within the admin panel.

Added plan-based monitor limit. Free plan supports up to 3 monitors; paid plans support up to 5–30.
Added plan-based minimum check interval. Free plan supports intervals of 5 minutes or more; paid plans support as low as 1 minute.