Dude.
I mean, I guess technically I don’t know what emotions Apple felt when it voluntarily posted this easy-to-find document, but it does spell out pretty clearly what information they can read. Basically, they (and therefore China) know who communicates with whom, but they can’t read any of the content, except with email, as is the case for anyone not using PGP or similar.
End-to-end encryption is a function of the phone, not the server farm, so to read actual messages or documents they’d have to have Chinese users use a different version of iOS.
