Dark mode support was added to version 2.20.31 (released in March of 2020) of the WhatsApp client. This is an iOS 13-only feature, and from the look & feel it appears to
I've asked eurodev support about this and just received:
At this point we don’t have any additional information about the unrestricted entitlement that you are asking about. The only information that’s available is linked here.
https://developer.apple.com/documentation/bundleresources/entitlements
Pushing back to them to get more info.
Thanks.