WhatsApp for Oppo Reno 12

WhatsApp's official iOS-to-Android move only works while the Oppo is factory-fresh, so do it during first-time setup: when ColorOS shows the Android setup wizard, open WhatsApp on the iPhone (Settings > Chats > Move Chats to Android), then scan the QR code shown on the Oppo and connect the two phones with a USB-C cable (use a Lightning-to-USB-C adapter if your iPhone has a Lightning port). If your Reno 12 is already set up, the only reliable way is to back up first, then factory reset it (Settings > System settings > Back up and reset > Erase all data) and run the move during the initial setup wizard, since the official transfer can't be triggered afterward. See how others solved this on Reddit

ColorOS aggressively freezes background apps to save battery, which delays or silences WhatsApp pushes. Go to Settings > Battery > App battery management, select WhatsApp and choose Allow background activity / Don't optimize (some builds label this Unrestricted). Then in Settings > Apps > App management > WhatsApp > Notifications confirm every category and lock-screen alerts are enabled. Finally, open Recent apps, swipe down on the WhatsApp card (or tap the menu) and tap Lock so the system can't clear it from memory. See how others solved this on Reddit

This is a permissions problem on ColorOS. Open Settings > Apps > App management > WhatsApp > Permissions and enable Display over other apps (floating windows) and Display on Lock screen. Then enable startup for WhatsApp under Settings > Apps > Startup manager (older builds call it Auto launch) so it can wake the screen for incoming calls. Lastly set WhatsApp to Allow background activity / Unrestricted under Settings > Battery > App battery management, otherwise the call arrives late or only as a missed call. See how others solved this on Reddit

If the call comes through but the screen stays dark, ColorOS has put WhatsApp into deep sleep. In Settings > Battery > App battery management, set WhatsApp to Unrestricted / Allow background activity and turn off any Sleep or pause-if-unused toggle for it. Also enable WhatsApp in Settings > Apps > Startup manager (Auto launch) and grant Display over other apps and Display on Lock screen under WhatsApp > Permissions, so the app is allowed to turn the display on for an incoming call. See how others solved this on Reddit

When the chat list shows stale previews even though the conversation itself is up to date, ColorOS is freezing the app process in the background. Open Recent apps and Lock the WhatsApp card, then set it to Allow background activity in Settings > Battery > App battery management. If the list is still stuck, Force stop WhatsApp via Settings > Apps > App management > WhatsApp > Force stop and reopen it, and make sure WhatsApp is updated to the latest version from the Play Store. See how others solved this on Reddit

Start by updating WhatsApp in the Play Store and clearing its cache via Settings > Apps > App management > WhatsApp > Storage usage > Clear cache (this won't delete your chats). If problems continue, set WhatsApp to Unrestricted under Settings > Battery > App battery management and confirm it has Startup/Auto launch and background-activity permission. As a last resort, back up your chats to Google Drive (WhatsApp > Settings > Chats > Chat backup), then uninstall and reinstall the app. See how others solved this on Reddit