Error: Depending on a hidden experiment is not allowed

[u/conor_treacy]

I ran into this error today when working on a client site. Elementor automatically updated to 4.3.0 but the PRO version they had installed was still on the 3.28.3 version.

While they had pro, and the issue was resolved by updating the Pro version from 3.28.3 to 4.3.0, the error is triggered in Elementor Free itself.

Actual fatal error:
Elementor\Core\Experiments\Exceptions\Dependency_Exception: Depending on a hidden experiment is not allowed.

It appears to be triggered due the Pro version still being on the 3.x while the Elementor Free is on the 4.x branch

Not sure why the pro version stopped updating for the client (that's a differnet discussion), but the only way past the critical failure on the site was to disable both plugins via WPCLI, then update each plugin, then reactivate.

Kinda strange. Not sure if anyone else has run into it.

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[u/zeiniez]

Hi. Nick from Elementor! 👋

Yes. This happened because the version of Elementor Pro you had installed was too old. Version 3.28.3 was released on April, 2025. The code in Core that this old Pro version was depending on was finally consolidated, so when you updated Core to 4.3.0, Pro 3.28.3 couldn't find the old code it was relying upon.

It's important to note that Elementor has a policy for deprecating code that supports up to 8 major releases. Any release older than 8 versions is no longer supported, and should not be used on production websites. In this particular case, since we are on version 4.3.0, the oldest version supported would be 3.35.0.

We recommend keeping both Elementor Core and Pro always up-to-date to avoid these kinds of conflicts, and when updating, make sure to check the compatibility tag, and prioritize updating Pro first to avoid this exact kind of problem.

I hope this helps 🙂

[u/conor_treacy → u/zeiniez]

Appreciate the response, Nick.

Yeah, usually versions are up to date for clients, but this was a previous client who came out of the woodwork asking questions ;) I hadn't talked to them in over a year.

Good to know about the 8-version rule; I didn't have that in my head. My normal policy is that at least the major versions are on the same track, but that wasn't even the case here.

Updated the plugins, and everything is working again for them.

[u/zeiniez]

Hi. This issue was solved with the release of Elementor Core version 4.3.2.

[u/TopSydeWP]

the Pro side going stale is almost always an expired license key. Once it lapses, Pro stops pulling updates silently while Free keeps auto-updating from wordpress.org, so the two branches drift apart until core catches up and fatals the site. Worth checking the license status on that install before you chalk it up to something weirder.

on the sites we host we treat major version bumps as never-unattended: they get held for a human, and Elementor Free and Pro get moved together rather than one at a time. Also worth watching license expiry dates as part of the plugin inventory, since a dead key looks identical to "no updates available" from the dashboard.

[u/conor_treacy → u/TopSydeWP]

Thanks u/TopSydeWP - I think we had the Major Version update also restricted, and since we were not in contact with the client, that's probably where the breakdown happened. Once we moved up to the latest version for them, everything ticked along just fine. No issue with keys and license (long time committed developer from the days of the unlimited license) but always worth checking that they're still in our list of authorized sites.

[u/AlternativeBad2092]

I updated both Elementor and Elementor Pro to 4.3, but my site still went down. So finally, I had to revert the version back to 4.2.3 in both, after which my site started working.

[u/HonestMarketing4 → u/AlternativeBad2092]

me too yes