No, iOS 18 currently does not support in-line replies for RCS. Replies from an Android phone appear as separate messages and do not reference the original message. However, with the new RCS update, Apple will have to implement in-line replies for RCS messages.
RCS on iPhones is designed to improve messaging between iPhones and Android devices by introducing features such as high-quality photo and video sharing, read receipts, typing indicators, and better group chat functionality. This upgrade aims to provide a more seamless and enhanced messaging experience for both iOS and Android users.
iOS 18, featuring RCS, is likely to be released in the fall, possibly in September, based on the information available from the iOS 18 beta releases and Apple's typical release schedule for major iOS updates.