Two important Modules but same override of validateOrder

[EricCasal]

Hello everybody!
For my shop i need two modules:

Delivery Dates Wizard Pro to allow customers to choose delivery times and dates:
https://addons.prestashop.com/en/delivery-date/20307-delivery-dates-wizard-pro.html#support-and-updates

Additional Product Attributes / Custom Product Fields to add mode checkboxes, radio buttons, options in general for a customizer.
https://addons.prestashop.com/en/combinaisons-customization/30960-additional-product-attributes-custom-product-fields.html

 

But i can only enable one of the two modules. When i try to activate the other it says (translated):
Enable of Module Productfields not possible: The override can not be installed: The Method validateOrder of the Class PaymentModule has been overridden by deliverydateswizardpro

 

I dont know how to solve this problem but i really need both modules to make my shop work. 
I hope you can help me. PrestaShop 1.7.6.4

Thank you for your time!

[joseantgv]

Contact the developer from the second module that you purchased (the one that you can install/enable) and ask him to merge both overrides.