System requirements
The same minimum versions are stated in the header of every plugin file. Beyond that, individual features need certain PHP extensions or server properties. If any of that is missing, the interface says so clearly instead of silently leaving the feature out.
Minimum versions
- WordPress 6.2 or higher
- PHP 8.0 or higher
Both are stated in the header of each of the eight plugin files. Which versions are actually running on this installation is shown by every plugin under “System” → “Guide” right at the bottom.
What individual features additionally need
- ZipArchive: Without this PHP extension, Backup cannot write or read any archives — the diagnostics then report “MISSING — backups impossible”. The batch export of the Consent proof records as a ZIP is also unavailable without it.
- OpenSSL: needed for the AES-256 encryption of the backups. If it is missing, encryption stays off and backups keep running.
- Writable uploads directory: Backup stores its archives under wp-content/uploads/kwpb-backups, and the page cache from Performance stores its files under wp-content/uploads/kwpp-cache.
- Free disk space: The Backup diagnostics rate more than 200 MB as unproblematic. Before every run, the “Advance estimate” card additionally estimates the requirement and blocks the start button if the space demonstrably is not enough.
- WP-Cron: backups, retention, reports and the daily integrity run all depend on it. If DISABLE_WP_CRON is set, the diagnostics report “disabled (system cron required)”.
- PHP max_execution_time: “unlimited” or at least 60 seconds counts as fine.
- Apache or LiteSpeed: The browser cache rules from Performance are written into the .htaccess as a block of their own and only take effect there.
- Outgoing HTTP connections: Security fetches the core checksums live from api.wordpress.org, and remote administration talks to the REST interface of the target sites.
Checking the requirements yourself
- Open Kakapo Backup and choose “Status” on the left in the “Status” group.
- Take a look at the “Diagnostics” card — it checks live every time you open it.
- With “Check again” you additionally write the result to the log.
- Rows marked red have to be fixed; yellow ones limit individual features.
Among other things, the diagnostics check whether a lock file can be created in the backup directory. If that does not work — for example because of missing write permissions or because of open_basedir —, no backup run can be carried out.
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