How to Check WordPress Plugin Compatibility Before Updating

WordPress updates and plugin updates occasionally break things. Log Deprecated Notices is one tool for catching compatibility issues early. Here is a complete process for safely updating WordPress and plugins.

Why Updates Break Things

WordPress updates change APIs. When a function is deprecated, it still works but is scheduled for removal. When it is actually removed in a future version, plugins that still call it break. Similarly, plugin updates can change internal behaviour that other plugins depend on, or can introduce conflicts with themes that hook into plugin actions and filters.

Most updates go smoothly. The ones that do not tend to follow major version jumps (WordPress 5.x to 6.x) or updates to heavily-used plugins (WooCommerce, Elementor, ACF) that have many dependencies.

The Staging Site Workflow

The safest approach is always to update staging before production:

1. Create a staging copy of your production site. Most managed hosts (WP Engine, Kinsta, SiteGround) have a one-click staging feature. Duplicator or WP Staging plugin work for other hosts.
2. On staging, update everything — WordPress core, all plugins, all themes.
3. Test the staging site thoroughly: homepage, key pages, forms, WooCommerce checkout, user login and registration.
4. If nothing is broken, apply the same updates to production.

Using Log Deprecated Notices on Staging

Activate Log Deprecated Notices on your staging site. Browse the site after updating — visit the homepage, post pages, shop, account area, and admin screens. Then check the deprecated notices log in admin. Notices that reference functions being removed in the next WordPress version indicate plugins or theme code that needs to be updated before the next major WordPress release.

If deprecated notices come from a plugin you rely on, report them to the plugin developer immediately. If the plugin is frequently updated, they may already have a fix in development.

Using Health Check and Troubleshooting Plugin

The Health Check and Troubleshooting plugin is invaluable for update testing. Its Troubleshooting Mode lets you switch to a default WordPress theme and disable all plugins for a specific browser session without affecting other visitors. This lets you test the site in a clean environment and re-enable plugins one at a time to identify conflicts — all while the production site remains up for other visitors.

PHP Compatibility Checker

Before upgrading PHP version (which hosting providers occasionally prompt for), run the PHP Compatibility Checker plugin. It scans all installed plugins and themes for code that is incompatible with the target PHP version and reports specific files and line numbers. Fix or update incompatible plugins before upgrading PHP.

What to Do When an Update Breaks the Site

If an update causes a white screen or broken functionality:

1. Access the site via FTP or hosting file manager.
2. Rename the plugin folder of the recently updated plugin (e.g., /wp-content/plugins/problem-plugin to /wp-content/plugins/problem-plugin-disabled). This deactivates it without needing wp-admin access.
3. Check if the site recovers.
4. If it does, you have identified the problem plugin. Report the issue to the developer and restore the previous version from your backup while waiting for a fix.

For managed WordPress update workflows, plugin compatibility testing, and staging environment setup, a WordPress developer can implement a safe update process that protects your production site.