With the launch of iOS 18, Apple added support for RCS, or Rich Communication Services. RCS replaces SMS/MMS as the default messaging standard for any "green bubble" conversations, and because it's more modern, it supports features like read receipts and typing indicators.
RCS is also supposed to support emoji reactions from Android users, but it wasn't working properly when iOS 18 launched. It's not clear what changed, but The Verge says that something that Google or Apple tweaked made it work as of this week.
When an Android user uses an emoji reaction to a message that you've sent over RCS, the emoji will now show up in line with the message bubble, just like it does on with iOS Tapback reactions.
Prior to now, if an Android user used an emoji reaction to a message in a conversation with an iPhone user, the emoji would show up on a separate line, which was confusing and not how the feature was meant to work.
The Verge says it tested emoji reactions between iPhones running iOS 18.1 and several different Android phones, and reactions display both ways as intended.
