The Active Directory Schema is a living platform that receives changes with every new Windows version. You check what each schema version does by looking at the ldf files in Support\ADPrep folder on the installation media.

This is done during the Adprep, before you promote a new Windows Server to a Domain Controller.

Schema Version	Introduced with
13	Windows 2000
30	Windows 2003
31	Windows 2003R2
44	Windows 2008
47	Windows 2008R2
56	Windows 2012
69	Windows 2012R2
87	Windows 2016
88	Windows 2019