Download all ADMX definitions from : https://support.microsoft.com/en-us/help/3087759/how-to-create-and-mana…

Create temp directory C:\admx on local domain-joined client

Install each ADMX version into its own subdirectory (C:\admx\7)
Merge all versions into C:\admx\all

From domain-joined client, connect to \\{pdc.yourdomain.tld}\sysvol using Domain Admin credentials (Map network drive if required).

Copy entire directory and contents from C:\admx\all\PolicyDefinitions to \\{pdc.yourdomain.tld}\sysvol\Policies\

All Group Policies, including the latest, can be searched using Microsoft's online Group Policy Search Tool : https://gpsearch.azurewebsites.net