https://techcrunch.com/2019/06/05/with-ios-13-apple-locks-out-apps-from-accessing-users-private-notes-in-contacts/

Apple is closing a loophole that allowed app developers to access users’ potentially sensitive and private data. With the launch of iOS 13, apps that request access to users’ Contacts will no longer be able to read the data in the “Notes” field of those address book entries.

For years, security professionals have warned people not to store private information in their phone’s Address Book because it’s not protected or encrypted in any way. And that makes it vulnerable.