Title: 404 Solution
Author: Aaron
Published: <strong>5 maart 2017</strong>
Last modified: 14 mei 2026

---

Plugins zoeken

![](https://ps.w.org/404-solution/assets/banner-772x250.jpg?rev=1614763)

![](https://ps.w.org/404-solution/assets/icon-256x256.jpg?rev=1610739)

# 404 Solution

 Door [Aaron](https://profiles.wordpress.org/aaron13100/)

[Download](https://downloads.wordpress.org/plugin/404-solution.4.1.18.zip)

 * [Details](https://nl.wordpress.org/plugins/404-solution/#description)
 * [Beoordelingen](https://nl.wordpress.org/plugins/404-solution/#reviews)
 *  [Installatie](https://nl.wordpress.org/plugins/404-solution/#installation)
 * [Ontwikkeling](https://nl.wordpress.org/plugins/404-solution/#developers)

 [Ondersteuning](https://wordpress.org/support/plugin/404-solution/)

## Beschrijving

Stop losing visitors and search rankings to broken links. **404 Solution automatically
redirects 404s to the right page** — not just your homepage — using a 7-engine matching
pipeline that includes a spell-checking algorithm to find what visitors actually
typed.

**Example:** A visitor hits `/prodcut/awesome-item` (typo). Most 404 redirect plugins
send them to your homepage. 404 Solution’s spell-checker finds `/product/awesome-
item` and redirects them there automatically.

#### Why 404 Solution Is Different

Most redirect plugins fall into two categories: tools that require you to manually
write every rule, or tools that blindly send every 404 to your homepage. 404 Solution
does neither.

 * **A spell-checking algorithm that actually matches typos.** Using Levenshtein
   distance and N-gram scoring, 404 Solution catches `/prodcut/`, `/categroy/`, 
   and `/wooocmmerce/` and finds the real destination — something no other free 
   plugin does.
 * **7 matching engines, in sequence.** Slug match  URL fix  Title keywords  Category/
   tag paths  Content search  Spelling similarity  Archive fallback. The first engine
   with a confident match wins.
 * **Automatic, from day one.** Install and activate. 404 Solution starts capturing
   and redirecting immediately. You can tune it; you don’t have to.
 * **Redirect management when you need it.** Full manual redirect editor, regex 
   support, bulk actions, and CSV/JSON import compatible with Redirection’s export
   format.
 * **Debug mode that shows its work.** Enable debug logging and see exactly which
   engine chose a redirect and why — a level of transparency no competing plugin
   offers.
 * **Built for real-world hosting.** Self-healing database tables, auto-recovery
   from corruption, automatic log trimming, and zero wp-admin-wide banners.
 * **Ships with extras most plugins sell separately.** HTTP 410 Gone, 307/308/451
   status codes, Google Search Console integration, REST API, WP-CLI support, email
   digest reports, and security probe detection — all free.

#### Unlike plugins that blindly redirect to your homepage

A 404-to-homepage redirect tells Google your broken URL is the same page as your
homepage. That creates a soft 404 — a page Google may index as duplicate content,
eroding crawl budget and ranking over time.

404 Solution redirects to the _correct_ destination, or returns a proper 410 Gone
when content is permanently removed. Both outcomes are better for search engines
and for visitors.

#### How It Works

 1. A visitor reaches a URL that returns a 404.
 2. 404 Solution runs the URL through its 7-engine pipeline.
 3. Each engine tries to find a confident match above its score threshold.
 4. The first engine to find a match wins. The visitor is redirected to the correct
    page.
 5. The redirect is logged. You can review, edit, or delete it from the dashboard.

The whole process adds no perceptible latency for visitors on non-404 pages. The
matching pipeline only runs when a genuine 404 occurs.

#### Key Features

**Intelligent Automatic Matching**

 * 7-engine matching pipeline (slug, URL fix, title, category/tag, content, spelling,
   archive)
 * Levenshtein distance + N-gram scoring catches genuine typos
 * Per-engine confidence thresholds — tune aggressiveness per engine
 * Conditional engine groups — override the matching strategy for specific URL patterns
 * Slug-change auto-detection — redirects created automatically when you rename 
   a post
 * Trash/deletion monitoring — redirect created automatically when a post is deleted

**Redirect Management**

 * Manual redirect editor with bulk actions
 * Full regular expression support
 * CSV and JSON import/export (compatible with Redirection plugin format)
 * .htaccess and Nginx server-level export
 * Per-post and per-term exclusion via meta box
 * HTTP status codes: 301, 302, 307 (method-preserving temporary), 308 (method-preserving
   permanent), 410 Gone, 451 Unavailable For Legal Reasons, and Meta Refresh
 * GDPR-compliant: IP addresses are hashed before storage — never written to disk
   in plain text

**404 Monitoring and Logging**

 * Captures every 404 hit with referrer, user agent, and timestamp
 * Automatic log trimming with configurable disk usage limits
 * Security monitoring — flags vulnerability scanner probes (.env, /wp-config.php,
   phpMyAdmin, etc.)

**Reporting and Diagnostics**

 * Stats dashboard with traffic trend charts (404s, redirects, captures over time)
 * Email digest reports
 * Debug logging — see which engine fired and why
 * Google Search Console integration — import crawl errors and push fixes
 * Internal link scanner to find broken links before visitors do

**Developer and Integrator Tools**

 * REST API for redirect management
 * WP-CLI subcommands (list, create, delete, import, export)
 * Scheduled maintenance cron
 * Full WordPress Multisite support

**Compatibility**

 * WooCommerce (products, variations, categories, custom URLs)
 * Yoast SEO, Rank Math
 * WPML, Polylang, TranslatePress
 * Easy Digital Downloads
 * All custom post types and custom taxonomies

#### Perfect For

 * **eCommerce sites** (WooCommerce, EDD) with changing product URLs
 * **Content sites** with evolving permalink structures
 * **Migrated sites** where old URLs need to map to new content
 * **Large sites** with thousands of pages where manual redirects are impractical

## Schermafbeeldingen

 * [[
 * **Redirect Dashboard** — Active redirects with color-coded status badges (301,
   302, 307, 308, 410, 451), match confidence scores, and engine names. Filter by
   manual, automatic, or regex. Sort by any column.
 * [[
 * **Statistics** — Summary cards for redirects, captured URLs, and daily stats.
   Match confidence donut chart and 30/90-day trend analytics for 404 hits.
 * [[
 * **Debug Log** — Real-time debug output showing engine processing, spell-check
   scoring, candidate evaluation, and redirect decisions for every 404 request.
 * [[
 * **Captured 404s** — Every unhandled 404 logged with URL, hit count, first-seen
   and last-seen timestamps. Filter by captured, ignored, or later status.
 * [[
 * **Settings** — Configure automatic redirect behavior, custom 404 page, auto-deletion
   rules, default redirect type, and notification preferences.
 * [[
 * **Email Digest** — Weekly HTML email summarizing captured 404s, resolution rate,
   and a ranked table of top 404 URLs with color-coded hit badges.

## Installatie

 1. Unzip the files and upload the contents to `/wp-content/plugins/`.
 2. Activate the plugin.
 3. Use the `Settings -> 404 Solution` options page to set the options.

## FAQ

### How is this different from the Redirection plugin?

Redirection is a manual redirect manager — you write the rules, it applies them.
That is useful when you know in advance which URLs will break. 404 Solution handles
the URLs you don’t know about: it automatically finds the right destination using
a 7-engine matching pipeline and a spell-checking algorithm.

**Example:** If a visitor types `/prodcut/awesome-item`, Redirection does nothing
unless you manually created that specific rule. 404 Solution finds `/product/awesome-
item` automatically.

The two plugins are complementary. Many sites run both: Redirection for planned 
migrations and 404 Solution for everything else.

### How is this different from 404 to 301?

404 to 301 redirects ALL 404 errors to one fixed destination (usually the homepage).
404 Solution finds the actual page the visitor was looking for. Sending visitors
to your homepage is poor UX and can create soft 404 problems in Google Search Console.

### How is this different from WP 404 Auto Redirect to Similar Post?

WP 404 Auto Redirect uses keyword matching, which works when the URL contains recognizable
words from a post title. It fails on character-level typos — a URL like `/prodcut/`
has no keyword that matches “product.”

404 Solution adds Levenshtein spell-checking, which catches transpositions and typos
regardless of whether the keywords match. It also includes: full 404 logging, manual
redirect management, CSV import/export, 410/451 status codes, GDPR IP hashing, debug
logging, REST API, and WP-CLI support.

### What HTTP status codes are supported?

**301** (permanent redirect), **302** (temporary redirect), **307** (temporary, 
method-preserving), **308** (permanent, method-preserving), **410 Gone** (correct
response for permanently deleted content — better for SEO than a 301 to homepage),**
451 Unavailable For Legal Reasons**, and **Meta Refresh** (client-side HTML redirect).

Using 410 instead of redirecting deleted content to your homepage produces better
results in Google Search Console and prevents soft-404 indexing.

### Will this slow down my site?

No. The matching pipeline only runs when a genuine 404 occurs — normal page loads
are unaffected. For large sites, 404 Solution uses N-gram indexing and caching tables
to keep matching fast. Once a redirect is established, subsequent hits are served
from the redirect table directly, bypassing the pipeline.

### Does it work with WooCommerce?

Yes. 404 Solution indexes WooCommerce products, product variations, product categories,
and tags. When a product URL changes or a product is deleted, the appropriate redirect
is created automatically.

### What happens when a redirect destination is deleted?

404 Solution detects when a destination post is trashed or deleted and flags the
redirect. Redirects pointing to deleted content are highlighted in the redirect 
table so nothing slips through unnoticed. The daily maintenance cron automatically
removes orphaned auto-redirects.

### Can I import redirects from another plugin?

Yes. 404 Solution imports CSV and JSON in the Redirection plugin’s export format.
It can also directly import from Rank Math, Yoast SEO, AIOSEO, and Safe Redirect
Manager’s database tables from the Tools tab.

### Is it GDPR compliant?

Yes. IP addresses are hashed using a one-way algorithm before storage; the original
IP is never written to disk. Log retention limits are configurable. By default no
data is transmitted to external servers. The “Help the developer by sending error
logs” admin checkbox (default off) and the uninstall feedback modal are the only
opt-in paths that send data to the plugin author’s reports server. See the plugin’s
privacy policy stub at `docs/privacy.md` for the retention period for rows keyed
by site_url, the data-subject erasure path, and the processing region for the reports
endpoint.

### Does it support regex?

Yes. Manual redirect rules support full regular expression syntax for source URLs.

### Does it work with WPML, Polylang, or TranslatePress?

Yes. 404 Solution detects the active language from the multilingual plugin’s API
and resolves redirect destinations to the correct translated version automatically.

### Can I use WP-CLI to manage redirects?

Yes. 404 Solution includes WP-CLI subcommands for listing, creating, deleting, importing,
and exporting redirects — useful for scripted migrations and DevOps workflows.

### Does it work after a site migration?

Yes. 404 Solution is ideal for site migrations: slug-change auto-detection, URL 
typo correction (strips `.html`, `.php`, `.asp`), hierarchical category path resolution,
and regex redirects for bulk pattern changes.

### Can I redirect all 404s to a specific page?

Yes. Go to **Settings  404 Solution  Redirect all unhandled 404s to** and select
your preferred fallback page.

### How do I manage log files and disk usage?

Log cleanup is automatic. Configure maximum log size under **Options  General Settings
Maximum log disk usage**. You can also manually clear logs from the Logs page.

### Can I exclude certain URLs from being processed?

Yes. Use **Options  Advanced Settings  Files and Folders Ignore Strings** to add
paths to ignore. Per-post and per-term exclusion is also available via the edit 
screen checkbox.

### How do I exclude a specific post or page?

Edit the post/page and check the “Exclude from 404 Solution redirects” checkbox 
in the sidebar. Category and tag terms can also be excluded via term meta on the
edit screen.

### Have you written any other programs?

Check out [AJ Experience](https://www.ajexperience.com/) for other useful tools 
and resources.

## Beoordelingen

![](https://secure.gravatar.com/avatar/e9addbf23d2e222f1c426a091b6e83b23f0aea1df2ef55254396ae36ffb07b6f?
s=60&d=retro&r=g)

### 󠀁[AJAX error](https://wordpress.org/support/topic/ajax-error-78/)󠁿

 [ixoyewarrior](https://profiles.wordpress.org/ixoyewarrior/) 30 april 2026 3 reacties

when I look at all or captured 404s I get this message after a lengthy spinning 
wait:404 Solution: AJAX error while updating the table.HTTP status: textStatus: 
timeout errorThrown: timeout action: ajaxUpdatePaginationLinks subpage: abj404_captured

![](https://secure.gravatar.com/avatar/d1a6ede61023b135c5288e1c28a9cf3ec22babdae7333a48d2f65d2b68699ae8?
s=60&d=retro&r=g)

### 󠀁[Works as expected; fast support!](https://wordpress.org/support/topic/works-as-expected-fast-support/)󠁿

 [PluginRx](https://profiles.wordpress.org/apos37/) 30 april 2025 1 reactie

I haven’t tried all of the features that this plugin has to offer as I intended 
to just use it temporarily to redirect users to a designated 404 page, but it does
so much more. I really appreciate the logs that show me the crazy urls people/bots
are trying to access. Had a minor issue with a php notice that I reported, and the
developer quickly jumped on it and released an update. Kudos!

![](https://secure.gravatar.com/avatar/89f236fbda264a5de710ae9168d31437b3bd4c5468973c46a249a6688e62a72c?
s=60&d=retro&r=g)

### 󠀁[Thank you for your great plugin!!!!](https://wordpress.org/support/topic/thank-you-for-your-great-plugin-2/)󠁿

 [frondmedia](https://profiles.wordpress.org/frondmedia/) 3 oktober 2024 1 reactie

It is working great, frequent updates from the developer and is our seo saver!!!
Thank you for your great job!

![](https://secure.gravatar.com/avatar/3b2b6685590fff4e957ab3f2d881691c4d6fb4ae6decce9930db3d1086069b65?
s=60&d=retro&r=g)

### 󠀁[Type to filter error](https://wordpress.org/support/topic/type-to-filter-error/)󠁿

 [fikret20](https://profiles.wordpress.org/fikret20/) 1 januari 2024 2 reacties

Ajax error when I want to search in the filtering section. I get Result: “parsererror”,
error: {} error. Is there a solution? Thank you in advance for your reply.

![](https://secure.gravatar.com/avatar/5606abb46ea12dae6d08eb60ff24aafe568f95406a73b3b70315a9daad59ba71?
s=60&d=retro&r=g)

### 󠀁[Ottimo](https://wordpress.org/support/topic/ottimo-541/)󠁿

 [Fabrizio Pieroni](https://profiles.wordpress.org/fabriziopieroni/) 18 december
2023 1 reactie

Lo uso da un po’ e non ha mai creato problemi

![](https://secure.gravatar.com/avatar/9ad8028c0e84e4e321488590012ffcca9662da86a0b25eeb4bbe86f9ec1f63e7?
s=60&d=retro&r=g)

### 󠀁[I am SO happy to find this plugin…](https://wordpress.org/support/topic/i-am-so-happy-to-find-this-plugin/)󠁿

 [crzyhrse](https://profiles.wordpress.org/crzyhrse/) 10 oktober 2024 1 reactie

I am SO happy to find this plugin…… It is head and shoulders above every other similar
plugin, in every way… Thank you so MUCH for making it available… 🙏🌻 P.S… Plus,
when an issue did come up later, after I first did this review, the plugin author
fixed it nicely in a timely manner…

 [ Lees alle 42 beoordelingen ](https://wordpress.org/support/plugin/404-solution/reviews/)

## Bijdragers & ontwikkelaars

“404 Solution” is open source software. De volgende personen hebben bijgedragen 
aan deze plugin.

Bijdragers

 *   [ Aaron ](https://profiles.wordpress.org/aaron13100/)

“404 Solution” is vertaald in 4 localen. Dank voor [de vertalers](https://translate.wordpress.org/projects/wp-plugins/404-solution/contributors)
voor hun bijdragen.

[Vertaal “404 Solution” in je eigen taal.](https://translate.wordpress.org/projects/wp-plugins/404-solution)

### Interesse in ontwikkeling?

[Bekijk de code](https://plugins.trac.wordpress.org/browser/404-solution/), haal
de [SVN repository](https://plugins.svn.wordpress.org/404-solution/) op, of abonneer
je op het [ontwikkellog](https://plugins.trac.wordpress.org/log/404-solution/) via
[RSS](https://plugins.trac.wordpress.org/log/404-solution/?limit=100&mode=stop_on_copy&format=rss).

## Changelog

#### Version 4.1.18 (May 13, 2026)

**Bug Fixes**

 * Fixed the admin table cache rebuild getting stuck on the same step after a dropped
   database connection. The rebuild now auto-resumes from where it stopped on the
   next request, instead of retrying the same failing query forever.
 * Fixed admin actions that hit an expired session nonce showing a generic “security
   check failed” error. The session is now silently refreshed and the action retried,
   so the expiry is invisible to the administrator.
 * Fixed transient invalid AJAX responses on admin tables producing “undefined” 
   errors. The admin pages now validate the response shape before reading it and
   surface a clear error instead.
 * Fixed the “missing database table” admin notice being cleared by the next successful
   query in the same request, so the admin never saw it. The generic auto-clear 
   now skips the missing-table notice; that notice is cleared only by the dedicated
   repair-success path.

**Improvements**

 * Captured 404s and Page Redirects admin tables load noticeably faster on large
   sites. The total log-count query is now cached on the maximum log id (avoiding
   a full log-table scan on every page load), log queries no longer sort by non-
   indexed columns, the Most Unused Redirects report reads from the pre-aggregated
   hits rollup instead of scanning raw logs, and the dashboard activity trend is
   cached between admin page loads.
 * When WordPress cron is broken and the log hits rollup falls behind, the plugin
   now surfaces an admin notice on its own pages explaining how to fix it, instead
   of silently letting the admin tables show stale numbers.

**Internationalization**

 * Added translations for 13 admin strings that were previously displayed in English
   even on non-English sites.

#### Version 4.1.17 (May 10, 2026)

**Bug Fixes**

 * Fixed repeated “Access denied” errors and silently-stuck Captured 404s and Page
   Redirects pages on shared and managed hosting environments where certain database
   privileges are restricted. The rebuild now skips the affected step and continues,
   instead of retrying the same denied operation on every cron run and emailing 
   the site administrator.
 * Fixed the rebuild silently never starting on managed or sharded MySQL services(
   such as PlanetScale and Vitess) that do not support standard MySQL named locks.
   The plugin now uses an alternate locking mechanism on these hosts.
 * Fixed the rebuild getting permanently stuck after a previous run was interrupted(
   for example, by a server restart mid-rebuild). The plugin now detects and cleans
   up leftover state at the start of the next rebuild so it can complete normally.
 * Fixed the rebuild silently waiting forever when WordPress scheduled tasks (cron)
   are disabled and no external cron is configured. The plugin now shows a clear
   admin notice with guidance on how to resolve it.
 * Improved compatibility with multisite networks during long-running rebuilds that
   span multiple background tasks.
 * Improved compatibility with persistent object caches (Redis, Memcached) so that
   rebuild progress is reliably saved even when the cache layer is briefly inconsistent.
 * Improved compatibility with HyperDB, LudicrousDB, and other custom database drop-
   ins.

**Improvements**

 * The plugin now self-detects unusual PHP and database hosting limits (memory limit,
   time limit, strict SQL modes, query packet size) at the start of each rebuild
   and adapts to work within them, instead of failing on restrictive hosts.

#### Version 4.1.16 (May 8, 2026)

**Bug Fixes**

 * Fixed the Captured 404s and Page Redirects admin pages getting stuck on “Creating
   build buffer (1/11)” forever on hosts with the standard 30-second PHP execution
   limit (the default on most shared hosting). The cache rebuild was yielding before
   inserting any rows because it was reserving more PHP time than the request actually
   had, so each rebuild request returned without making progress. The first batch
   of every rebuild step now always runs, so the rebuild reliably moves forward 
   on a typical 30-second host.
 * Fixed Captured 404s and Page Redirects admin pages still failing to load when
   the database killed a single rebuild step (max statement time exceeded, lost 
   connection, lock timeout): the entire rebuild used to give up, but it now resumes
   on the next request from where it left off, at every step.
 * Fixed brief network blips and intermittent 5xx responses during a long rebuild
   causing the admin page to show “Could not finish refreshing data” instead of 
   continuing to wait. Transient errors are now treated as a no-progress tick and
   the page keeps polling.
 * Fixed the rebuild getting stuck retrying the same single-statement step (index
   build, hit-count update, or sort-index step) when the host’s database statement
   timeout was shorter than that step needed to complete. Those steps used to retry
   with the same too-tight timeout forever; now the per-query timeout is extended
   for the retry so the step can finish.

**Improvements**

 * The admin-table rebuild now adapts its batch size to the host. If a batch is 
   killed by the database, the next attempt uses a smaller batch, and the smaller
   size is remembered for the rest of the rebuild so slow shared hosts converge 
   on a size they can actually finish.
 * Per-query timeouts during the rebuild are now sized to the host’s own statement
   timeout (MariaDB max_statement_time / MySQL max_execution_time), so a kill produces
   a clean classifiable error the rebuild can resume from rather than a dropped 
   connection.

#### Version 4.1.15 (May 6, 2026)

**Bug Fixes**

 * Fixed a plugin load fatal on PHP 7.4 to 8.1 hosts that was introduced in 4.1.14.
   A constant inside a trait (added with the staged view rebuild) is only valid 
   in PHP 8.2 and later; the declared minimum is PHP 7.4, so this restores compatibility
   for all supported PHP versions.

#### Version 4.1.14 (May 6, 2026)

**Bug Fixes**

 * Fixed Captured 404s and Page Redirects admin tables getting stuck or returning“
   Could not load table data” on very large sites while the table cache was being
   rebuilt. The rebuild now resumes in small background steps and the admin screen
   keeps polling progress until the data is ready.
 * Fixed a race where an admin table could retry too soon after a background rebuild
   started, causing repeated loading failures instead of waiting for the rebuilt
   data.

**Improvements**

 * The Captured 404s and Page Redirects admin tables now use a staged cache rebuild
   that splits expensive destination, status, and hit-count work into bounded batches.
   Large sites should see more reliable table loading without long-running AJAX 
   requests.
 * Added clearer in-page progress handling while the admin table cache is warming,
   so administrators can tell the plugin is still working instead of seeing a static
   loading state.

#### Version 4.1.13 (May 2, 2026)

**Bug Fixes**

 * Fixed “Could not load table data” timeouts on the Captured 404s and Page Redirects
   admin tables. On sites with a large WordPress posts table, the count query now
   skips unrelated JOINs when no search filter is active, and admin table caches
   are warmed in the background across multiple short requests instead of one long
   one — so the tables reliably load even when individual queries are slow.

**Improvements**

 * The plugin admin footer now includes a collapsible Debug Info section showing
   per-stage AJAX timings, errors, and database query timings for the Captured 404s
   and Page Redirects views. When reporting a slow or stuck admin table, you can
   copy this directly without opening browser developer tools.
 * SQL errors are now recorded before any automatic recovery (table repair, retry
   with a relaxed collation) runs, so the original cause of a failing query stays
   visible in the support log instead of being overwritten by the recovery attempt’s
   own messages.

#### Version 4.1.12 (May 1, 2026)

**Bug Fixes**

 * Fixed Captured 404s and Page Redirects table AJAX requests timing out while background
   log-cache maintenance was running. Maintenance that is triggered by an AJAX table
   load now runs through scheduled background tasks instead of shutdown work tied
   to the same HTTP request.
 * Fixed debug-log setup failing on sites with negative or fractional WordPress 
   timezone offsets.
 * Fixed diagnostic logging paths that could throw while trying to report another
   error, which could hide the original problem behind a secondary logging failure.

#### Version 4.1.11 (May 1, 2026)

**Bug Fixes**

 * Fixed loss of captured-404 history when the database performed automatic repair
   of a crashed log table. The plugin previously dropped and recreated the affected
   table after repeated repair failures, destroying logged hits in the process. 
   It now leaves the table alone if repair cannot succeed, preserving your captured-
   404 history.
 * Fixed loss of log data during repair of damaged plugin tables that were missing
   their primary key column. This was the underlying cause of the log-history loss
   reported during the 4.1.6 to 4.1.7 upgrade. The repair now preserves all existing
   rows instead of recreating the table from scratch.
 * Fixed timeouts during the nightly log-cache rebuild on sites with aggressive 
   log retention. The rebuild now reliably completes within shared-host time limits.

**Improvements**

 * The Captured 404s list and other admin views that read log data now load substantially
   faster on sites with large log tables. A new indexed column replaces a slower
   per-row computation; existing sites are updated in the background during nightly
   maintenance and speed up over time.

#### Version 4.1.10 (Apr 30, 2026)

**Bug Fixes**

 * Fixed disk-full, read-only, and crashed-table conditions encountered during log
   flush and N-gram cron scheduling escalating to error level and triggering developer
   email reports. These hosting conditions are now classified as warnings — the 
   plugin already degrades past them — so they no longer spam the admin’s inbox.
 * Fixed admin AJAX error notices showing only generic HTTP/textStatus information
   when a paginated admin view timed out or returned a 500. The notice now includes
   the elapsed request time, the server-side processing stage that was in flight
   when the failure occurred, and the redacted SQL of the failing query when available,
   so the cause is identifiable without a server log dump.
 * Fixed a parse-time fatal on PHP 7.4 through 8.1 caused by two trait-level constants
   introduced with the canonical-URL backfill work. The constants are now declared
   on the using class so the trait file parses cleanly on every supported PHP version.

**Improvements**

 * The Page Redirects and Captured 404s admin views are now significantly faster
   on installs with very large redirects tables. Each redirect now stores a precomputed
   canonical URL that is indexed and JOINed against the hits rollup, eliminating
   the per-row CONCAT/TRIM evaluation that could time out the admin AJAX request
   on sites with hundreds of thousands of captured rows. The column is backfilled
   in chunks during the upgrade and the nightly maintenance cron, so large sites
   converge across cron ticks without blocking any single request.
 * The daily cron that flags dead-destination redirects now scales with URL count
   rather than raw log-row count. The query now JOINs against the precomputed `logs_hits`
   rollup with a new `failed_hits` column, completing in milliseconds even on sites
   with millions of log rows where it previously timed out.
 * The admin AJAX timeout for explicit user actions (sorting, filtering, pagination)
   was raised from 15 seconds to 45 seconds. Background detect-only refreshes still
   use the tight 15-second budget, so the longer timeout only applies when the admin
   is actively waiting.
 * Several catch blocks across the plugin that previously swallowed exceptions silently
   now emit a warning breadcrumb to the support log, so unexpected failure paths
   are visible in support bundles instead of vanishing.

#### Version 4.1.9 (Apr 29, 2026)

**Bug Fixes**

 * Fixed potential over-deletion of log history during the daily cron cleanup. The
   destructive DELETE was sized using an approximate row count from MySQL metadata,
   which can drift by orders of magnitude on InnoDB. The cron now gates the delete
   on an exact byte-size check before deciding what to remove.
 * Fixed captured-URL counts undercounting when the same URL was logged with and
   without leading or trailing slashes (e.g. `/foo`, `foo`, `/foo/`). URL variants
   now collapse to a single canonical row in the hits rollup, restoring slash-tolerant
   matching that regressed in 4.1.7.
 * Fixed Email Digest dropping captured URLs that had zero recent hits. The “Top
   Captured 404s” section now lists captured rows with no hits as well as those 
   with hits, matching the on-screen behavior.
 * Fixed Email Digest rendering a misleading “No captured 404s in this period” notice
   while the hits rollup was being rebuilt. The digest now ships with an explicit“
   Top URLs unavailable: log rollup is being rebuilt” message instead.
 * Fixed the high-impact captured-count cache holding a value of zero for 24 hours
   when the rollup was unavailable or the query errored. The result is now cached
   only on a successful query, so the count recovers on the next page load.
 * Fixed the Stats trend chart cache being polluted with empty results when the 
   trend query errored or timed out.
 * Fixed admin search inputs on Page Redirects and Captured 404s rendering a stray“
   O”-shaped SVG glyph above the search box.
 * Fixed the health bar “unavailable” indicator rendering as a transparent dot during
   rollup rebuild — it now displays as a muted gray dot to communicate the transient
   state.
 * Fixed every frontend 404 falling through to the theme 404 page on installs where
   the database upgrade could not complete (corrupted DDL files, opcache divergence,
   restrictive shared hosting). The redirect lookup now falls back to a schema-tolerant
   query against the existing redirects table, so manual redirects keep firing while
   the upgrade is stuck. Trade-off: scheduled redirects briefly stop honoring their
   start/end windows during the degraded window.
 * Fixed asynchronous page suggestions failing to surface for long or low-overlap
   404 URLs. The async worker now prioritizes recall over worst-case latency, since
   it already runs out-of-band and is rate-limited.
 * Fixed admin tables remaining stuck on “Loading…” indefinitely when the AJAX request
   to fetch table data hangs (for example, while the plugin is recreating a missing
   database table on the slow path). The AJAX call now has a 15-second client-side
   timeout, the retry/fallback path replaces the loading rows with a clear error
   message instead of just stripping the placeholder attribute, and AJAX errors 
   render a non-blocking admin notice instead of a native browser `alert()` dialog.

**Improvements**

 * The Captured 404s and Page Redirects admin tables now render quickly even on 
   sites with millions of log rows. The high-impact captured count, the per-row 
   hit population query, the Email Digest top-captured query, and the Stats trend
   chart now all read from the pre-aggregated `logs_hits` rollup table, eliminating
   multi-second full-log scans that could time out behind Cloudflare and other reverse
   proxies.
 * Health bar AJAX is now decoupled from pagination — the redirects table renders
   immediately while the health bar hydrates in a separate request, so a slow rollup
   query no longer blocks first paint.
 * The daily cron now reads log row counts from MySQL `information_schema` metadata
   instead of running a full index scan on every nightly tick.
 * Permalink keyword cron updates are now issued as a single bulk SQL query instead
   of up to 500 single-row UPDATEs per cycle, sharply reducing database load on 
   busy sites.
 * The anonymous suggestion-compute endpoint now enforces a per-IP rate limit and
   rejects unauthorized requests before any plugin classes are loaded.

#### Version 4.1.8 (Apr 28, 2026)

**Bug Fixes**

 * Fixed a critical 4.1.7 regression where the `wp_abj404_logs_hits` cache table
   was dropped during the 4.1.6  4.1.7 upgrade and never recreated. Affected sites
   saw “Table doesn’t exist” errors flooding the debug log and triggering email 
   reports. Sites that already upgraded to 4.1.7 will have the table automatically
   recreated when they upgrade to 4.1.8 — the cache repopulates on the next scheduled
   rebuild. The destructive table-recreation step that caused this regression has
   been hardened to require positive evidence before dropping any table.
 * Fixed `mysqli_num_fields()` TypeError on PHP 8.1+ MariaDB sites caused by the
   new query timeout wrapper (4.1.7) being passed to `wpdb::get_results()` for non-
   SELECT queries. INSERT/UPDATE/DELETE/DDL queries now route through `wpdb::query()`
   so the wrapper no longer confuses WordPress’s query classifier.
 * Fixed view-cache table self-repair only running on the upgrade path. Activation,
   scheduled cron runs, and upgrade now all repair a stripped view-cache table before
   any further table maintenance, so broken installs heal themselves regardless 
   of how the plugin loads.
 * Fixed spurious “Table doesn’t exist” debug-log noise and a stale `.notice-error`
   admin banner during fresh installs. Pre-create maintenance queries are now silent
   when their target tables don’t yet exist.

**Improvements**

 * Collation mismatches between database tables are now repaired automatically and
   silently. Previously these surfaced as admin notices; the plugin now runs collation
   correction on detection (rate-limited to once per hour), retries the original
   query, and only logs at debug level — no user action required.

#### Version 4.1.7 (Apr 25, 2026)

**Bug Fixes**

 * Fixed HTTP 524 timeout error on the Captured 404s admin tab for sites behind 
   Cloudflare or other reverse proxies. The hits table rebuild query (which joins
   the logs table with redirects) is now split into a fast chunked pre-aggregation
   that scales to millions of log rows.
 * Fixed AJAX responses not being flushed before shutdown hooks, which could cause
   proxy timeouts even when the response data was ready.
 * Fixed ANALYZE TABLE running on every Settings page load, causing unnecessary 
   database overhead.

**Improvements**

 * All database queries now have automatic execution time limits (not just SELECT
   queries). INSERT…SELECT, UPDATE, DELETE, and DDL queries are also protected on
   MariaDB; INSERT…SELECT is also protected on MySQL.

#### Version 4.1.6 (Apr 23, 2026)

**New Features**

 * Automatic query timeout — all SELECT queries now include a server-side execution
   time limit, preventing runaway queries from locking the database on shared hosting.
 * WordPress URL-guess fallback — when no matching engine finds a redirect, the 
   plugin now tries WordPress’s built-in URL guessing as a last-resort redirect 
   before returning a 404.

**Improvements**

 * Admin pages now load instantly — all heavy database queries on the Redirects,
   Captured 404s, Logs, and Settings pages are deferred to AJAX, eliminating blocking
   page loads on large sites.
 * Optimized three slow view queries that could cause timeouts on sites with large
   redirect and log tables.

**Bug Fixes**

 * Fixed AJAX error state leaving placeholder loading attributes on admin tables,
   preventing interaction until page reload.
 * Fixed duplicate bottom table separator appearing after AJAX table hydration.
 * Fixed Logs page not loading via AJAX due to missing `.perpage` class on the per-
   page select element.
 * Fixed stray search filter and unwanted top pagination placeholders appearing 
   on admin pages.
 * Fixed SQL query referencing a non-existent column in the logs-hits join query.

#### Version 4.1.5 (Apr 22, 2026)

**New Features**

 * Simple mode Phase 3 — streamlined UI with contextual guidance, suggested destinations
   for captured 404s, and auto-created redirects for first-time users. Hides advanced
   columns and options in Simple mode for a cleaner experience.
 * Centralized Google OAuth — one-click Google Search Console connection via a Cloudflare
   Worker relay, replacing the manual client-ID setup.

**Bug Fixes**

 * Fixed “Illegal mix of collations” errors when WordPress core tables use `utf8mb3`
   and plugin tables use `utf8mb4`. Core columns are now wrapped with `CONVERT(...
   USING utf8mb4)` before applying `COLLATE`.
 * Fixed collation mismatch in `getPublishedImageIDs` query when comparing term 
   names across tables with different collations.
 * Fixed `opcache_invalidate()` emitting a PHP warning on hosts that restrict the
   function via `disable_functions` (e.g. some WP Engine/Flywheel configurations).
 * Fixed potential out-of-memory crash when the `logs_hits` fallback query ran without
   a row limit — now capped at 5,000 rows.
 * Fixed four small correctness issues in redirect filtering, view queries, settings
   save, and redirect-table rendering.

**Improvements**

 * Hardened admin page rendering against out-of-memory errors, corrupted options,
   and hook failures — the plugin now always shows its admin menu even when dependencies
   fail, and catches fatal errors with a shutdown handler fallback.
 * Migrated four redirect query methods to the centralized `queryAndGetResults()`
   handler for consistent error handling and retry logic.

**Internationalization**

 * Added Simple mode Phase 3 strings to all 17 locale PO files.
 * Added missing admin error message translations across all locale PO files.

#### Version 4.1.4 (Apr 20, 2026)

**Bug Fixes**

 * Fixed “Illegal mix of collations” errors on spell-checker and permalink-cache
   queries when plugin tables and WordPress core tables use different collations(
   e.g. `utf8mb4_unicode_520_ci` vs `utf8mb4_unicode_ci`). Extended the `COLLATE`
   protection pattern to `updatePermalinkCache.sql`, `getPublishedPagesAndPostsIDs.
   sql`, and `getIDsNeededForPermalinkCache.sql`.
 * Fixed redirect edit form rejecting type=0 (Default 404 Page) with “Data not formatted
   properly” error. The validation was unable to distinguish “no type provided” 
   from “type is 0” after int-casting.
 * Fixed plugin tables not being detected after a hosting migration or `$table_prefix`
   change in `wp-config.php`. The daily maintenance cron now triggers prefix adoption
   so orphaned tables are auto-recovered without requiring a manual deactivate/reactivate
   cycle.
 * Fixed transient PHP fatal errors during plugin upgrades on hosts with aggressive
   opcache settings (WP Engine, Flywheel, etc.) caused by stale bytecode from the
   previous version. Critical class files are now invalidated via `opcache_invalidate()`
   at the start of the upgrade.

**Improvements**

 * The daily maintenance cron now checks and converts table engines back to InnoDB,
   fixing persistent MyISAM reversions caused by hosting environments that reset
   the storage engine between plugin upgrades.

#### Version 4.1.3 (Apr 17, 2026)

**Bug Fixes**

 * Fixed spell checker throwing `get_object_vars()` TypeError on PHP 8+ when `get_term()`
   returns a non-object value (e.g. from a corrupted object cache). The tag and 
   category matching branches now use `is_object()` guards before accessing term
   properties.
 * Fixed Google Search Console integration returning HTTP 400 errors — the API does
   not support `groupType: 'or'` in dimension filter groups. Each URL is now queried
   individually.

#### Version 4.1.2 (Apr 16, 2026)

**Bug Fixes**

 * Fixed spell checker consuming ~61MB of memory on large sites — restructured the
   algorithm to use ~16KB regardless of site size.
 * Fixed a race condition in the `start_ts` column migration that could cause errors
   when multiple processes triggered the upgrade simultaneously.
 * Fixed HOME type pages displaying the wrong title in the suggestion results.
 * Fixed admin settings page showing a blank page instead of a visible error when
   the current user lacks the required permission.

**Improvements**

 * Added all SQL files to the boot integrity check, ensuring corrupted or missing
   schema files are detected during plugin startup.

#### Version 4.1.1 (Apr 9, 2026)

**Bug Fixes**

 * Fixed statistics page showing all zeros even when the logs page had data. Three
   separate bugs combined to cause this: the trend chart SQL was comparing `dest_url
   IS NULL` instead of `dest_url = '404'` (never matching real 404 entries); the
   stats dashboard returned an empty placeholder on first load instead of computing
   real data; and `getStatsCount()` threw an exception on empty query results, causing
   cascading failures that zeroed out all stats.

**New Features**

 * Added heartbeat debug log emails for opted-in sites. Sites with the “send error
   logs” option enabled now have a 1-in-100 daily chance of sending their full debug
   zip even when no errors are detected, confirming the error-reporting pipeline
   is working. Subject line reads “heartbeat” instead of “error” for easy filtering.

#### Version 4.1.0 (Apr 4, 2026)

**New Features**

 * Added built-in 404 suggestion page with one-click setup — selecting “Suggest 
   similar pages” automatically creates a page with the `[abj404_solution_page_suggestions]`
   shortcode. No manual page creation or shortcode knowledge required.
 * Simplified 404 behavior setting with visual tile picker — choose between “Suggest
   similar pages” (recommended), “Redirect to homepage”, “Custom page”, or “Theme
   default 404” with a single click.
 * Block editor notice when editing the system suggestion page — warns editors that
   the page is managed by 404 Solution to prevent accidental shortcode removal.

**Bug Fixes**

 * Fixed infrastructure database errors (disk full, read-only, crashed tables, connection
   lost) being logged at ERROR level from direct query call sites, triggering unnecessary
   developer email reports. All 17 direct-$wpdb error sites now use centralized 
   infrastructure error classification and log as WARN.
 * Fixed multisite cross-prefix missing-table errors being logged at ERROR level—
   when wp-cron references another subsite’s table, the error is now correctly classified
   as WARN since it’s not actionable from the current site’s context.
 * Fixed N-gram index creation failing when expected columns were missing from the
   logs table — now guards against missing columns before attempting index creation.
 * Fixed N-gram cache rebuild progress exceeding 100% in some edge cases.
 * Fixed “required” attribute remaining on custom page picker input when switching
   away from “Custom page” behavior tile.
 * Improved prefix mismatch diagnostic message to distinguish multisite installations(
   normal cross-subsite references) from single-site prefix mismatches (wp-config.
   php issue).

#### Version 4.0.4 (Mar 29, 2026)

**Bug Fixes**

 * Fixed multisite activation/upgrade skipping orphaned table adoption — batch methods
   now run adoption after table creation, ensuring migrated data is recovered on
   multisite networks.
 * Fixed DDL schema comparison failing on MariaDB servers that use `COLLATE=utf8mb4_unicode_ci`(
   equals sign) instead of MySQL’s `COLLATE utf8mb4_unicode_ci` (space), causing
   unnecessary schema rebuild loops.
 * Fixed `doEmptyTrash()` executing an empty SQL query when called with an unrecognized
   sub-page parameter — now early-returns after logging the error.
 * Fixed logs URL filter failing when `logsid` was passed as a non-string type, 
   causing a type error in `sanitizeForSQL()`.
 * Fixed invalid UTF-8 byte sequences in captured URLs corrupting log INSERT queries—
   added `mb_convert_encoding()` sanitization at the log entry boundary.
 * Fixed DDL normalization not stripping `DEFAULT NULL` (which is implicit for nullable
   columns), causing infinite schema diff loops on some MySQL versions.
 * Fixed orphaned table adoption running on every page load instead of once — adopted
   prefixes are now recorded in `wp_options` to prevent re-detection.
 * Fixed table adoption running before target tables existed — adoption now executes
   after `runInitialCreateTables()`.

**Internationalization**

 * Completed translations for all 204 pending strings across 12 languages.
 * Added proper `_n()` plural forms for redirect count strings.
 * Fixed culturally inappropriate translations and religious idioms in warning messages.
 * Fixed fuzzy flags, broken format specifiers, and missing slug translations in
   PO files.

#### Version 4.0.3 (Mar 28, 2026)

**Bug Fixes**

 * Fixed filter bar inputs and selects overflowing below their container’s bottom
   border due to WordPress admin styles setting an inflated line-height on form 
   controls.
 * Fixed Logs tab URL search input being too narrow — it now dynamically grows to
   fill available space.
 * Fixed database error notices not appearing on the plugin admin page when a table
   is missing or cannot be created.

#### Version 4.0.2 (Mar 28, 2026)

**New Features**

 * Orphaned table adoption — automatically detects and recovers plugin data left
   behind by site migrations or table prefix changes. Uses slug-matching verification
   to confirm data ownership before adopting.
 * Graceful admin screen when plugin files are missing or corrupt — instead of a
   white screen, shows a diagnostic page listing missing files with reinstall instructions(
   Error 18).
 * Improved pipeline trace display with color-coded status badges for easier log
   reading.

**Bug Fixes**

 * Fixed table prefix normalization — centralized 15+ direct `$wpdb->prefix` usages
   to go through the lowercased prefix helper, preventing “Table doesn’t exist” 
   errors on case-sensitive MySQL servers after table rename.
 * Fixed `renameAbj404TablesToLowerCase()` running unnecessarily on MySQL servers
   with `lower_case_table_names >= 1` (where MySQL already handles table name casing).
 * Fixed orphaned redirect cleanup failing on sites with non-default database table
   prefixes.
 * Fixed N-gram cache race condition where concurrent TRUNCATE and INSERT operations
   could corrupt the spelling cache.
 * Fixed timezone handling — replaced `date_default_timezone_set()` with WordPress`
   wp_date()` for timezone-safe date formatting.
 * Fixed ErrorHandler switch statement bug that could route errors to the wrong 
   handler.
 * Fixed `deleteSpecifiedRedirects` type filter not correctly constraining purge
   operations.
 * Fixed DDL schema comparison incorrectly flagging non-zero quoted integer defaults(
   e.g. `DEFAULT '1'` vs `DEFAULT 1`) as schema differences.

**Security**

 * Added defense-in-depth guard that prevents schema migrations from accidentally
   dropping all columns from a table.

**Internal**

 * Column-matched INSERT for table adoption — uses `SHOW COLUMNS` and `array_intersect`
   to handle schema drift between plugin versions when adopting data from old-prefix
   tables.
 * Major codebase refactoring: consolidated duplicated DataAccess patterns, unified
   AJAX security boilerplate into a shared trait, extracted shared helpers for multisite
   batch processing and DDL normalization.
 * Replaced `$_REQUEST[ABJ404_PP]` message bus with a typed `RequestContext` object.
 * Removed dead code: unused settings method, stale DDL builders, and redundant 
   index verification logic.

#### Version 4.0.1 (Mar 25, 2026)

**Bug Fixes**

 * Fixed perpetual “still differences” schema errors on the engine_profiles table
   caused by MySQL quoting numeric defaults differently than the goal DDL (e.g. `
   default '1'` vs `default 1`).
 * Fixed missing-table auto-repair flooding admins with error emails even when repair
   succeeded. Now only sends an email if repair actually fails.
 * Fixed blank screen after dismissing the review notice.
 * Fixed GSC integration sending unbounded API requests — added URL cap, corrected
   chunk size, and added a circuit-breaker.
 * Fixed full-table scan in log ID/URL query by adding LIMIT 500.
 * Fixed PHP 8.4 deprecation warning in CSV export (`fputcsv()` missing `$escape`
   parameter).
 * Removed dead PDF email attachment feature.
 * Fixed Logs table layout — long URLs no longer overflow into adjacent columns,
   and the Date column is no longer truncated.
 * Fixed redirect not firing on WordPress 6.9+ when `class-wp-font-face.php` sends
   output before headers.

**Improvements**

 * Added pipeline trace for per-request detail logging in the Logs tab — click the
   arrow on any log row to see every step of the redirect decision process.

## Meta

 *  Versie **4.1.18**
 *  Laatst geüpdatet **2 dagen geleden**
 *  Actieve installaties **10.000+**
 *  WordPress versie ** 5.0 of nieuwer **
 *  Getest t/m **6.9.4**
 *  PHP versie ** 7.4 of nieuwer **
 *  Talen
 * [Chinese (China)](https://cn.wordpress.org/plugins/404-solution/), [Dutch](https://nl.wordpress.org/plugins/404-solution/),
   [English (US)](https://wordpress.org/plugins/404-solution/), [German](https://de.wordpress.org/plugins/404-solution/)
   en [Russian](https://ru.wordpress.org/plugins/404-solution/).
 *  [Vertaal in je eigen taal](https://translate.wordpress.org/projects/wp-plugins/404-solution)
 * Tags
 * [404](https://nl.wordpress.org/plugins/tags/404/)[404 redirect](https://nl.wordpress.org/plugins/tags/404-redirect/)
   [broken links](https://nl.wordpress.org/plugins/tags/broken-links/)[redirect](https://nl.wordpress.org/plugins/tags/redirect/)
   [spell check](https://nl.wordpress.org/plugins/tags/spell-check/)
 *  [Geavanceerde weergave](https://nl.wordpress.org/plugins/404-solution/advanced/)

## Waarderingen

 5 van 5 sterren.

 *  [  42 5 sterren beoordelingen     ](https://wordpress.org/support/plugin/404-solution/reviews/?filter=5)
 *  [  0 4 sterren beoordelingen     ](https://wordpress.org/support/plugin/404-solution/reviews/?filter=4)
 *  [  0 3 sterren beoordelingen     ](https://wordpress.org/support/plugin/404-solution/reviews/?filter=3)
 *  [  0 2 sterren beoordelingen     ](https://wordpress.org/support/plugin/404-solution/reviews/?filter=2)
 *  [  0 1 sterren beoordelingen     ](https://wordpress.org/support/plugin/404-solution/reviews/?filter=1)

[Your review](https://wordpress.org/support/plugin/404-solution/reviews/#new-post)

[Bekijk alle beoordelingen](https://wordpress.org/support/plugin/404-solution/reviews/)

## Bijdragers

 *   [ Aaron ](https://profiles.wordpress.org/aaron13100/)

## Ondersteuning

Opgeloste problemen in de laatste twee maanden:

     3 van de 4

 [Het supportforum bekijken](https://wordpress.org/support/plugin/404-solution/)