WhatsApp for Xperia 10 V

First update WhatsApp from the Google Play Store, since outdated builds can crash on Sony's stock Android. If it still closes, go to Settings > Apps > WhatsApp > Storage & cache and tap Clear cache (not Clear storage, which deletes local chats), then reboot the phone. Also set Settings > Apps > WhatsApp > App battery usage to Unrestricted so the system isn't killing it in the background. See how others solved this on Reddit

Sony's audio tuning can interfere, so open Settings > Sound & vibration and turn off enhancements like 360 Upmix or Dolby Sound while on calls. In WhatsApp, open Settings > Storage and data and make sure 'Use less data for calls' is off, then check Settings > Apps > WhatsApp > Permissions to confirm the Microphone permission is granted. Cleaning the bottom mic and earpiece grilles also helps if the other side sounds muffled. See how others solved this on Reddit

Make sure WhatsApp has the Nearby devices and Phone permissions under Settings > Apps > WhatsApp > Permissions, since without them the headset's answer button may not trigger. Re-pair the device under Settings > Device connection > Bluetooth, and on the headset side ensure it's connected for both Media and Call audio. If the answer button still fails, answer on-screen and switch output to the headset from the in-call audio output icon as a workaround. See how others solved this on Reddit

WhatsApp uses its own basic in-app camera and heavily compresses media, so for the best results tap the attach (paperclip) icon, choose Gallery, and pick a photo you already took with Sony's Camera app instead of shooting inside WhatsApp. To reduce compression, go to WhatsApp Settings > Storage and data > Media upload quality and set it to HD. Capturing in the stock Camera app first, then sending from the gallery, gives noticeably sharper results. See how others solved this on Reddit

Yes. WhatsApp now supports a second account in-app: open WhatsApp Settings, tap the arrow next to your name, choose 'Add account', and register a second number (you'll need access to that number for the verification code). Alternatively, since the Xperia 10 V is dual-SIM, install WhatsApp Business from the Play Store as a fully separate app with its own number. Sony's stock Android has no built-in app-cloning feature, so these are the reliable options. See how others solved this on Reddit

The Xperia 10 V has no notification LED, so use the Ambient display instead: go to Settings > Display > Lock screen and enable 'Wake screen when notifications arrive' (and turn on Always-on display for a persistent indicator). For a stronger cue, open Settings > Apps > WhatsApp > Notifications and turn on 'Pop on screen' plus vibration. A third-party edge-lighting app from the Play Store can simulate an LED flash if you really want one. See how others solved this on Reddit