WhatsApp for Oppo Reno 8

ColorOS aggressively kills background apps to save battery, which is the usual cause. Go to Settings > Battery > App battery management, tap WhatsApp and set it to Allow background activity, and turn off Sleep standby optimisation. Then long-press the WhatsApp icon > App info > Notifications and make sure Allow notifications and all notification categories are enabled. See how others solved this on Reddit

ColorOS blocks the full-screen call popup unless WhatsApp has the right permissions. Go to Settings > Apps > App management > WhatsApp > Permissions and enable Display over other apps (floating windows), then under Settings > Battery > App battery management allow background activity and enable Auto-launch. In WhatsApp itself, open Settings > Notifications and confirm call notifications are on. See how others solved this on Reddit

This is almost always a date/time mismatch or a storage/permission issue. Set Settings > Additional settings > Date & time to Automatic so WhatsApp's certificate check passes, then clear WhatsApp's cache via Settings > Apps > App management > WhatsApp > Storage usage > Clear cache (not Clear data). If it persists, confirm WhatsApp has Files and media (or Photos and videos) permission and that you have free internal storage. See how others solved this on Reddit

WhatsApp needs photo and media access that ColorOS may have restricted. Go to Settings > Apps > App management > WhatsApp > Permissions and grant Photos and videos (or Files and media), choosing Allow all instead of Ask every time. Then clear the WhatsApp cache under Storage usage and restart the phone; if sharing from the Gallery still fails, update WhatsApp from the Play Store. See how others solved this on Reddit

Use WhatsApp's official 'Move to Android' tool rather than a backup, since iPhone backups live in iCloud and Android uses Google Drive. On a freshly set-up Oppo (do this during initial setup or after a factory reset), scan the QR code that appears using your iPhone, connect the two phones with a USB-C to Lightning cable, and follow the on-screen transfer steps. Both phones must use the same phone number, and keep WhatsApp updated on both before starting. See how others solved this on Reddit

When the chat list stops refreshing or shows old previews, it's usually a display/sync glitch worsened by ColorOS background limits. First update WhatsApp to the latest Play Store version, since this is a known bug fixed in newer releases. If it continues, force-stop WhatsApp via Settings > Apps > App management > WhatsApp > Force stop, clear cache under Storage usage, reopen it, and allow background activity in App battery management so it can sync in real time. See how others solved this on Reddit