typo3typo3-6.2.xdowngradetypo3-7.x

How to downgrade typo3 7.4.0 to 6.2.15

What are the steps to downgrade a typo3 site and is this even possible?

I cannot get a few plugins to work on my 7.4 typo site so I decided to downgrade but I cannot find anything about it on typo forums or in the documentation. Are there any steps I can follow if this is possible.

Solution

  • Before upgrading your website you should always backup your data and avoid downgrading at any time.

    Compatibility mode for TYPO3 6.x

    The system extension compatibility6 is shipped with TYPO3 7, have you tried installing this extension already?

    See also: Retaining compatibility to TYPO3 CMS 6

    Downgrading from 7.x back to 6.2

    There is no such thing as a documentation with downgrade instructions. But if you have no other option than you can try the following:

    Before running TYPO3 again:

    1. Backup your data
    2. Remove the TYPO3 7 core as well the composer.json (and /vendor/ directory), .htaccess and index.php file from your website.
    3. Remove the content of /typo3temp/, /fileadmin/_processed/ and /fileadmin/_temp_/.
    4. uninstall all TYPO3 7 related (system) extensions by setting the state to inactive in the /typo3conf/PackagesStates.php file.
    5. Uninstall or downgrade all extensions which are only compatible with TYPO3 7.x.
    6. Set manual the ['SYS']['compat_version'] in /typo3conf/LocalConfiguration.php to '6.0' (we let TYPO3 think that we are uograding from 6.0. Please note that TYPO3 7 doesn't have this option anymore and you need to create it yourself.
    7. Remove all array items from the array ['INSTALL']['wizardDone'] in /typo3conf/PackagesStates.php.
    8. Set manual options such as ['FE']['activateContentAdapter'] back if needed.
    9. Put the TYPO3 6.2 core back in it's place.

    Now you're allowed to run TYPO3 again:

    1. Log in on the install tool by accessing /typo3/install/.
    2. Run the database compare but please don't remove fields or tables that belongs to extensions which you have temporary disabled for downgrading purposes.
    3. Clear all caches from the install tool.
    4. Run al steps from the upgrade wizard.
    5. Reactivate disabled extensions (manually).
    6. Check if the ['SYS']['compat_version'] is set to '6.2'.
    7. Test your TYPO3 instance as good as you can.