The release of iOS 18 saw that Apple has added Rich Communication Services or RCS support, replacing MMS/SMS as its default “green bubble” chatting standard, adding typing indicators and read receipts to see if the person has read your message.
The RCS Feature is also expected to support Android emoji reactions, with Apple or Google believed to have made fixes for this because it wasn’t working when iOS 18 was first released. This works when a person who uses an Android device reacts with an emoji to a message sent using RCS, making the emoji show in the same line as the message bubble, similar to the reactions on iOS Tapback.
Before this update, whenever Android users send an emoji reaction to another iPhone user in a conversation, it shows in a different line- potentially conveying another message or causing confusion, which wasn’t how the feature was supposed to work.