problem Updating in Prestashop 1.7.7.8.3

[rimas06]

We have a problem with our multishop store. Now we are unable to adjust the products, prices,
information of the products or any pictures at all. At any shop of 3 shops. Updated to PS version 1.7.7.8.3 and PHP at server
is 7.4.27. When we open the cataloque at category level / list of products, we can see the small pictures of the product,
product name & number...
But when clicking some product and opening the info sheet(picture, texts,prices), no picture is shown at all. And no updates allowed.
At different product combinations and prices, unable to update anything.
We have abled/unabled different modules one by one ( also PS modules), no improvment.
Any idea which could cause the problem/problems?
At advanced adjustments in back office, we can find a list of overrides:
classes/Hook.php
classes/Link.php
classes/form/CustomerPersister.php
classes/controller/FrontController.php
classes/controller/Controller.php
classes/db/Db.php
classes/Product.php
classes/Media.php
classes/Dispatcher.php
controllers/front/ProductController.php
controllers/admin/AdminCmsController.php
controllers/admin/AdminManufacturersController.php
controllers/admin/AdminMetaController.php
controllers/admin/AdminCategoriesController.php
controllers/admin/AdminSuppliersController.php
controllers/admin/AdminCmsCategoriesController.php


Is this normal?

 

[essss2]

Change back to php 7.3 or even better to 7.2. Enable dev mode (to see error messages), and delete var/prod cache folder.

 

[zyhivan]

great module for import! Thank you so much! Thank you so much!