Oppo
Turn Chat Features On or Off in Messages auf Oppo
Chat features are Google's implementation of RCS (Rich Communication Services) inside the Messages app. They add read receipts, typing indicators, high-resolution media sharing and better group chats on top of standard SMS and MMS.
Many carriers turn this on automatically once your Oppo phone connects to their network and verifies your number. If that verification fails, or the setting resets after a system update, Messages falls back to plain SMS/MMS and features like delivery receipts or larger attachments disappear.
You can check and change the state manually with this path:
Tap on Messages ➔ Open the Menu ➔ Tap on Settings ➔ Tap on General ➔ Tap on Chat features ➔ Enable or disable Chat features
Enable Chat features if your carrier supports RCS and you want richer messaging with contacts who also use it. Disable them if you are troubleshooting delivery problems, roaming on a network with weak RCS support, or you want messages to fall back reliably to SMS/MMS.
Turning Chat features off does not delete your message history. It only changes how new messages are sent and received. Contacts without RCS support will always get standard SMS/MMS regardless of this setting.