Mortise 2 min read

Find broken links after a theme or plugin update

Theme and plugin updates rewrite menus and templates. Inspect once for the mess, then baseline so the next silent break is an alert — not a customer email.

A WordPress (or any CMS) theme or plugin update can change header menus, footer link widgets, related-post blocks, and "skip to" templates without touching your posts. The failure mode is a 404 that used to be a 200. Treat it like a small migration: inspect, fix, baseline.

Right after the update

  1. Smoke-check the homepage and one inner template in a private window.
  2. Run SiteCheck on the public URL for a current defect list (free: up to 25 pages, no account). Fix broken nav and template links first.
  3. If redirects appeared (old pretty-permalink shapes), straighten chains — how to find and fix redirect chains and loops.

A full migration playbook (DNS cutovers, large URL renames) is in how to find newly broken links after a website migration. A theme update is the same logic on a smaller blast radius.

Then baseline

Once the site is in a state you accept, verify it in Mortise. The first crawl is silent. Later crawls alert only after a previously working link fails twice as 404 or 410. Known leftovers stay quiet — why broken-link checkers keep reporting the same broken links.

Free: 1 site, 200 pages, manual check once per day, dashboard only, no card. Pro ($12/month or $79/year): schedule, email, webhook, more sites and pages.

Re-baseline after the next major theme change if you intentionally restructure URLs; otherwise leave the baseline alone so regressions stay visible.

Checklist

  • Update applied on a backup or staging first when you can.
  • Live SiteCheck (or equivalent) after production update.
  • Obvious template 404s fixed.
  • Mortise baseline taken on the cleaned site.
  • Optional: SignalWatch on pricing/homepage if copy also lives in the CMS — watch your own website for unexpected edits.