WhatsApp for Samsung Galaxy Avant

The Galaxy Avant ships with Android 4.4 KitKat, and current WhatsApp builds require Android 5.0 or newer, so the Play Store shows no compatible update for this hardware. Confirm your Android version under Settings > About device > Software info; if it is below the WhatsApp minimum, the official app will not update further on this phone. To keep messaging working you will need to move your account to a newer device, since sideloading old APKs from outside Google Play is unsafe and stops working as the protocol changes. See how others solved this on Reddit

On older TouchWiz builds this is usually a notification setting. Go to Settings > Apps > Application manager > WhatsApp and make sure Show notifications is enabled, then open WhatsApp > Settings > Notifications and confirm Call notifications and the ringtone are turned on. Also check that lock-screen notifications are allowed under Settings > Sound and notification (or Settings > Lock screen) so incoming-call alerts are not hidden while the screen is locked. See how others solved this on Reddit

On the Avant, open WhatsApp > Settings > Chats > Chat backup and run a manual backup to Google Drive using the same Google account you will sign into on the new phone. On the new Samsung, install WhatsApp from the Play Store, verify the same phone number, and accept the restore prompt that detects the Drive backup. The Google account and phone number must match exactly, or the new device will not find the backup. See how others solved this on Reddit

Yes, WhatsApp keeps a local copy in phone storage even without a Drive backup. On a KitKat device like the Avant the backups live at Internal storage > WhatsApp > Databases. Using a file manager, place the msgstore.db.crypt12 file in that Databases folder, then uninstall and reinstall WhatsApp and verify the same number so it offers a local restore. The phone number must match the one that created the backup, and a local file can only restore data up to the date it was saved. See how others solved this on Reddit

First confirm the SIM has signal and can receive normal text messages, then enter your number with the correct country code and wait the full countdown timer. When the timer ends, choose Call Me to receive the code by voice instead of SMS. Make sure Settings > Date and time is set to automatic, since a wrong clock on an aging device can block delivery, and check that no call-blocking or message-filtering app is rejecting WhatsApp's shortcode before you retry. See how others solved this on Reddit

The simplest route is to connect the phone to a computer with a USB cable, swipe down and set the USB mode to File Transfer (MTP), then copy the DCIM folder off the device. Alternatively install Google Photos from the Play Store and turn on Back up & sync so images upload to your Google account, where you can grab them from any newer phone. WhatsApp photos and videos on this device are stored separately at Internal storage > WhatsApp > Media. See how others solved this on Reddit