Error: Class PrestaShopBundle\Form\Admin\Extension\ModifyAllShopsExtension contains 1

[Leaderone]

I installed PrestaShop version 8.1.2, and then I encountered error messages when I tried to log into BackOffice. I did not succeed in solving the problem. Then I uploaded the full file of the store to FTP for version 1.7.9.10, and now this message appears when I try to login to BackOffice:

 

(1/1) FatalErrorException

Error: Class PrestaShopBundle\Form\Admin\Extension\ModifyAllShopsExtension contains 1 abstract method and must therefore be declared abstract or implement the remaining methods (Symfony\Component\Form\FormTypeExtensionInterface::getExtendedType)

in ModifyAllShopsExtension.php line 49

 

-----

Please help me solve this problem

[musicmaster]

Sorry, when you start mixing versions the chaos becomes too big. I can't help with that.