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We Removed Critical Version Checking

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Docket Cache 26.04.09, released on 13 October 2026, removed an old option called Critical Version Checking. With it, the plugin no longer contacts api.docketcache.com. This is a short post about what the option did, and why it is gone.

What it did#

We added Critical Version Checking in version 20.09.01, in October 2020, in the early days of Docket Cache.

Docket Cache saves each cache entry as a PHP file. In the early days, it wrote these files with Symfony VarExporter. PHP has its own var_export() function, but on PHP 7.2 it cannot export a stdClass object in a way that loads back. It writes stdClass::__set_state(), and that method does not exist, so loading the file fails. PHP 7.3 fixed this.

Since version 22.07.03, in February 2023, Docket Cache uses the native var_export() when it can, for arrays and objects that hold no class other than stdClass. It is built into PHP, so Docket Cache does not need to load VarExporter for these values.

In the early versions, the way Docket Cache wrote cache files still changed from release to release, and files written by an older version could cause errors after an update. We needed a way to tell sites to clear their cache after they updated to a version like that.

When the option was on, the main site of each install sent a request to api.docketcache.com every few days, and in later versions every 15 days. The reply could name a version as critical. When the site later updated to that version, Docket Cache cleared the whole cache after the update.

Each request sent these details.

The option was on by default until version 21.08.01, in August 2021. After that, it was off unless you turned it on in the Configuration screen or with the DOCKET_CACHE_CHECKVERSION constant.

Why we removed it#

The problem it was made for belongs to the early days. A cache plugin should not need to ask a server what to do with its own files.

Since 26.04.10, every cache file holds a format version. When a release changes the format, Docket Cache sees the older files when it reads them, deletes them and builds the values again. Each site does this on its own, after any update, without a request to anyone. Our post What Went Wrong In 26.04.10, And How 26.04.11 Fixed It shows this in action.

There is also less to trust. A site that never contacts our server does not depend on it being online, and does not send us anything.

What changed for you#

Nothing, in most cases. The option was off by default for more than five years.

If you had turned it on, 26.04.09 removes the scheduled event that sent the request. If your wp-config.php still has a line for DOCKET_CACHE_CHECKVERSION, it does nothing now, and you can delete it.

What Docket Cache still sends#

The only outside service left in Docket Cache is Cronbot. It pings your site every hour to keep WordPress cron running. It is not connected by default. Docket Cache only talks to it after you connect it on the Cronbot screen, and you can disconnect it at any time.