We assume you have composer-based TYPO3 installation with extension
Make Backups or work on a development system
Create a backup of your database and filesystem before applying these steps. It is highly recommended to use this extension on a development system only.
composer req b13/container
Keep EXT:gridelements installed for now.
composer req --dev sbublies/gridtocontainer
See the chapter on Installation. Make sure the TypoScript template is included. We install the extension as a dev-requirement as it should not be used on productive systems.
Check which of the available grid elements are in use
Go to the module Admin tools > Grid migration provided by this extension. See also What grid elements do i have on my site?.
Create alternative containers for each grid element
See the EXT:container documentation.
Migrate all grid elements to containers
Using the module Admin tools > Grid migration migrate all grid elements to the respective containers. See also Migrate grid elements from gridelements layout key.
Optional: Migrate FlexForm content
If your grid elements used FlexForms you have to migrate the values stored in the FlexForms by other means. See chapter Known problems.
Check the migration
Is everything being displayed as expected in frontend and backend?
Remove EXT:gridelements and this extension
Remove or replace all extensions that require EXT:gridelements and remove the requirement from your sitepackage. Then remove EXT:gridelements. You can also remove EXT:gridtocontainer after successfully migrating all containers:
composer remove gridelementsteam/gridelements sbublies/gridtocontainer
Clean up the database
Search in the database for content elements that still use the
-1and resolve them. See chapter Clean up the database for details.
Make a database compare
Got to Admin tools > Maintenance > Analyze Database and undo all changes that EXT:gridelements made to your database.