C5 upgrade 8.5.* to 9.0.2

I have 2 distinct errors:

  • Upgrading from 8.5.7 to 9.0.2 doesn’t work. I do not get the same error as the following thread: forums dot concretecms period org/t/v9-upgrade-from-8-5-6-breaks/1409
  • Upgrading from 8.5.4 to 9.0.2 gives access denied errors after editing and/or adding a block, then publish, as admin

I upgrade my Concrete5 environments using the method as described on the upgrade manual:
documentation period concretecms dot org/developers/introduction/installing-concrete-cms/upgrading-concrete
Replacing the original Concrete Directory (Version 8 and above)

After succesfully going through all the steps, I encounter the following issue when upgrading my websites from 8.5.7 to 9.0.2:

I’ve tried downgrading it from 8.5.7 to 8.5.4, but it gives the exact same result. Steps used below:

mv concrete/ concrete-oud/
mv updates/ updates-oud/
mv application/config/update.php application/config/update.php-oud
cp -r /home/concrete5-8.5.4/concrete/ .
chown -R select:select concrete/
-visits website to patch the upgrade through, no errors-
mv concrete/ concrete-8.5.4/
cp -r /home/concrete-cms-9.0.2/concrete/ .
chown -R select:select concrete/

On a completely different website, that already starts with version 8.5.4, the upgrade goes flawlessly. But when I add or edit a block, default Concrete blocks or custom blocks alike, the following error pops up with every page visit:


Upgrading the website to 8.5.7 first seems to give the first error.

What’s going on and how do I get rid of both of these errors, regardless of starting version?

Kind regards,


Apologies for avoiding the system for new users, I am in a hurry irl

  1. Upgrade from v8 to v9 is not yet officially supported
  2. If you want to experiment, first upgrade to v8.5.7

Downgrade can only be done by reverting to a backup.

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Thank you very much. How will I know when this will be officially supported? This goes both for using the manual upgrade as well as the composer upgrade.

It will only be officially supported when it appears as an option in the site dashboard.

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