1. Is it a fatal error?
A critical-error notice, a blank page or an HTTP 500 is a code failure with its own method: preserve the first error, keep debug output away from visitors and work on a copy. If this is you, use the critical-error guide and job. Otherwise continue.
- Critical error guide.
- Critical-error job.
2. Does one feature fail on a working page?
A button, form, menu or slider that fails while the page loads is usually a conflict or a stale script. Write the failing action as steps, reproduce it on a copy and change one thing at a time. The conflict guide gives the order and what to record.
- Conflict isolation guide.
- Conflict job.
3. Did a page layout change?
Spacing, stacking order, missing headers and a different phone layout point to generated styles, layout-type differences or an add-on. Compare against a baseline at three widths. The Elementor guide covers one popular builder.
- Layout guide.
- Layout restoration job.
4. Did the PHP version change?
A newer PHP version can break an old plugin that was fine before. Scan the plugin for the target version, then run it on a copy at that version. Decide whether to patch, update or replace.
- PHP compatibility guide.
- Single-plugin compatibility job.
5. Did the update erase your theme edits?
If custom changes vanished after a theme update, they were made inside the theme's files. Find every difference against a clean copy of the same version and move the keepers into a child theme.
- Child theme guide.
- Child theme job.
6. Did addresses change?
If a restructure or permalink change broke old links, map each old address to its new one and redirect once. Check preferred addresses and the sitemap.
- Redirects guide.
- Redirect map job.
7. Stop it happening again
Try updates on a staging copy before they reach the live site and record a pass or hold for each. The routine guide explains it; the standing service (published test price GBP 145 a month for up to twenty updates) does it for you on a private staging copy without touching the live site. Prices are untested proposals and payment follows the agreed checks.
- Update routine guide.
- Standing staging-test service.
Sources and limits
- WordPress documentation: Manage Plugins Checked 2026-10-11.
- A current backup should exist before updating, deactivating plugins one at a time can find a conflict, and must-use plugins cannot be disabled from the plugins screen.
- PHP: supported versions Checked 2026-10-11.
- PHP branches have two years of active support and two of security support, after which they are end of life.