Visit your OXID backend and navigate to Extensions > Modules > Ratepay > Root to deactivate your current Ratepay Payment Plugin.
Remove the folder pi_ratepay which you can find in
{shop-root}/source/modules/pi.Create then a new folder named ratepay.
Copy all files of the Ratepay Payment Plugin into that new folder.
Visit the root folder of your OXID Shop installation and open the composer.json file.
Add the following autoload configuration:
"autoload": { "psr-4": { "pi\\ratepay\\": "./source/modules/pi/ratepay", "Ratepay\\": "./source/modules/pi/ratepay/vendor/ratepay/php-library/src" } },Connect via ssh to the server where you find your shop installation and it's vendor folder.
Execute the following command to generate the required autoloader files:
vendor/bin/composer dump-autoloadAfter successful execution you should get these responses:
Generating autoload filesGenerated autoload filesNow empty the tmp and cache folders
Visit your OXID Shop backend and navigate to Extensions > Modules and confirm with Yes that the old configuration can be deleted.

- Visit your OXID Shop backend and navigate to Extensions > Modules > Ratepay > Root to activate your all new plugin and reconfigure the module settings.
- Visit your OXID Shop backend and navigate to Shop Settings > Payment Methods to activate your Ratepay payment methods.
Go to Ratepay Setting