WhatsApp is a great way to stay in touch with loved ones, but you do not want to lose all conversation when you switch handsets. It's very easy to secure your messages directly from WhatsApp. Here's the skinny.
First, open WhatsApp and tap the three-dot menu in the top right corner.
Tap Chat Backup.
 Chats screen ” width=”320″ height=”656″ src=”/pagespeed_static/1.JiBnMqyl6S.gif” onload=”pagespeed.lazyLoadImages.loadIfVisibleAndMaybeBeacon(this);” onerror=”this.onerror=null;pagespeed.lazyLoadImages.loadIfVisibleAndMaybeBeacon(this);”/>] Tap "Back up to Google Drive." Choose how often the chats should be backed up.
Tap on your Google Account.
. At the Drive prompt, tap "Allow."
Use the green "BACK UP" button to instantly secure your chats. After that, your messages will be restored according to the schedule you set.
to restore your WhatsApp messages from Google Drive.
If you want to set up a new phone, open WhatsApp. Enter your phone number to sign in.
Verify your phone number with a text message.
Select Continue to view the contact and save prompts.
Tap the green "Restore" button.
WhatsApp displays the backup found. the total size and the number of messages that will be recovered. Touch the green Next button.
Continue with the WhatsApp setup and you will see your old news. Then pick up your calls right where you left off!