wkwebview quite possibly brought a major version update, but it sure didn't include the patch we needed. Whether that was because Apple works from a fork that didn't include that patch or the major version was still older than the version we needed, I don't know. There was just no way to get that kind of information out of them.
iirc there was some way to figure out what version of WebKit a given iOS device was using and it was definitely pre patch.
Surely they must sync up, but when? Unless you work inside Apple there's just no way to know. Pretty frustrating as a developer trying to build for their platform.