Download WhatsApp for your phone

One UI's aggressive battery optimization is the usual culprit, so go to Settings > Apps > WhatsApp > Battery and set it to Unrestricted. Then open Settings > Battery > Background usage limits and make sure WhatsApp is removed from both the Sleeping and Deep sleeping app lists, and confirm notifications are fully enabled in WhatsApp's own Settings > Notifications. See how others solved this on Reddit

First update WhatsApp through the Play Store, since older builds can crash on HyperOS. If it still fails, back up your chats first via WhatsApp > Settings > Chats > Chat backup, then go to Settings > Apps > Manage apps > WhatsApp > Clear data and reinstall the latest version. A corrupted cache after a HyperOS update is the usual cause. See how others solved this on Reddit

Crashes are usually caused by an outdated app build or a corrupted cache. First update WhatsApp from the Play Store, then go to Settings > Apps > Manage apps > WhatsApp > Clear data and tap only 'Clear cache' (avoid 'Clear data', which logs you out and can remove local chats). If it still crashes, back up your chats via WhatsApp Settings > Chats > Chat backup, then uninstall and reinstall WhatsApp from the Play Store. See how others solved this on Reddit

HyperOS aggressively kills background apps to save battery, which blocks WhatsApp's call signaling so calls only appear once you open the app. Go to Settings > Apps > Manage apps > WhatsApp and set Battery saver to "No restrictions," then enable Autostart on the same screen. Next open Settings > Apps > Manage apps > WhatsApp > Other permissions and turn on "Display pop-up windows while running in the background." After this, incoming calls ring even when the app is closed. See how others solved this on Reddit

Google and WhatsApp support an official iOS-to-Android move, but it has to be done during the Pixel Fold's initial setup using a USB-C cable. In the setup wizard choose to copy data from an iPhone and connect the cable, then when you open WhatsApp on the Fold and sign in with the same phone number, follow the prompt to scan the QR code: WhatsApp shows the code on the Fold and you scan it with the iPhone to start the import. If you've already finished setup, you can't add the chats later without factory resetting and running the cable transfer again, since the chat-history import only happens through that initial Switch flow. See how others solved this on Reddit

Several users report choppy scrolling and slow chat-opening on the 17 Pro running iOS 26, which points to a WhatsApp build not yet optimized for the new OS. First update WhatsApp: open the App Store, tap your account photo in the top-right, scroll to the list of pending updates and update WhatsApp (or use the search tab to find it and tap Update). Then swipe WhatsApp closed from the App Switcher and reopen it. If it still lags, delete the app and reinstall it from the App Store, then restore your chats from your iCloud backup when prompted during setup. See how others solved this on Reddit

After an iOS update, force-close WhatsApp by swiping it away in the App Switcher, then reopen it, and check the App Store for a pending WhatsApp update since post-iOS releases often need the matching app build. If it still misbehaves, restart the iPhone 16 Plus (hold the Side button + either Volume button, then slide to power off) and confirm WhatsApp has Background App Refresh and Notifications enabled under Settings > Apps > WhatsApp. See how others solved this on Reddit

Lag is usually a bloated local database, so open WhatsApp Settings > Storage and Data > Manage Storage and clear large forwarded videos and media-heavy chats. Then force-close the app (swipe up from the bottom and flick WhatsApp away), make sure both iOS and WhatsApp are fully updated in the App Store, and reboot the phone. If a single chat scrolls slowly, clearing that chat's media or archiving it typically restores smooth performance. See how others solved this on Reddit

This is usually a WhatsApp build that isn't yet optimized for iOS 26 and the A19 Pro chip, so make sure you're on the latest version from the App Store and that iOS itself is current under Settings > General > Software Update. If it still stutters or freezes, force-close WhatsApp from the App Switcher and clear oversized media via WhatsApp > Settings > Storage and Data > Manage Storage, since bloated caches are the most common cause of the lag on this model. A restart of the phone after updating also clears the problem for most people. See how others solved this on Reddit

Most stutter and freezing on the 16 Pro traces back to an outdated app build or a stale cache after an iOS update. Update WhatsApp in the App Store, then force-quit it (swipe up from the bottom and flick the card away) and restart the phone; if it persists, offload it via Settings > General > iPhone Storage > WhatsApp > Offload App and reinstall, which clears the app's cache without deleting your chats. See how others solved this on Reddit