WhatsApp for Oppo Find X3 Pro

ColorOS aggressively kills background apps, so go to Settings > Battery > tap the three-dot menu > App battery management (or Battery usage), find WhatsApp and set it to 'Allow background activity' / turn off optimization. Also open Settings > Apps > App management > WhatsApp > Notifications and make sure the 'Calls' channel is enabled with sound and pop-up allowed. Finally, lock WhatsApp in the Recent Apps screen (open recents, swipe down on the WhatsApp card or tap the icon, then tap Lock) so the system stops clearing it from memory. See how others solved this on Reddit

This is usually aggressive power management blocking the screen from turning on for incoming VoIP calls. Go to Settings > Apps > App management > WhatsApp and enable 'Allow auto-launch', then under the app's Battery usage set it to 'Allow background activity'. Also turn on 'Display over other apps' / 'Display pop-up windows while running in the background' in the app's permissions so the call screen can appear. If the issue started after a ColorOS update, clearing WhatsApp's cache and rebooting often restores the wake-on-call behaviour. See how others solved this on Reddit

Delayed and duplicated notifications usually come from ColorOS battery restrictions resetting after updates. Go to Settings > Battery > tap the three-dot menu > App battery management, find WhatsApp (and any affected app) and set it to 'Allow background activity'. Then in Settings > Apps > App management > WhatsApp enable 'Allow auto-launch' so it can start in the background. Turning off 'Sleep standby optimization' in the Battery settings also stops the system from throttling notifications overnight. See how others solved this on Reddit

Post-update glitches like WhatsApp crashing or freezing are often fixed by clearing the app cache (not the data): go to Settings > Apps > App management > WhatsApp > Storage usage > Clear cache. If that doesn't help, update the app from the Play Store and restart the phone. As a last resort, Settings > System settings > Back up and reset > Reset phone > Reset system settings clears configuration left over from the old ColorOS version without deleting your data. See how others solved this on Reddit

WhatsApp's iCloud backup can't be restored on Android, so use the official 'Move to Android' transfer. Install WhatsApp on the Oppo and start setup with the same phone number; when it shows a QR code, open WhatsApp on the iPhone and go to Settings > Chats > Move Chats to Android, then scan that code. Keep both phones plugged in and on the same Wi-Fi during the transfer. The regular Google Drive backup only works for chats already on an Android phone, not for migrating from iOS. See how others solved this on Reddit

First try a forced restart by holding Power and Volume Down together for around 15-20 seconds until the Oppo logo appears, since ColorOS can hang in a black-screen state that looks like a dead phone. Leave it on the charger for at least 30 minutes with the original charger and cable, because a deeply drained battery may show no charging indicator for several minutes. If there's still no response after charging, it points to a battery or board fault that needs Oppo service. See how others solved this on Reddit