Do this while you still have both phones working and charged. Almost everything that goes wrong in a phone change goes wrong because the old phone was already sold, wiped or broken.
Before you touch the new phone
- Charge both phones past half.
- On the old phone, run a WhatsApp backup by hand: Settings, Chats, Chat backup, then Back up. Wait for it to finish. This is the step people skip and regret.
- Check your contacts are in your Google or iCloud account, not on the phone or SIM. The backup guide covers how.
- Write down which phone number your WhatsApp and your bank apps are tied to, and make sure that SIM is going into the new phone.
Android to Android
New Android phones walk you through this during setup. When the new phone asks about copying apps and data, choose to copy from another device and follow it. You will either use a cable that came in the box or a Wi-Fi connection between the two phones.
It moves apps, accounts, settings, call history and photos. It takes twenty minutes to an hour depending on how much you have.
If you have already finished setting up the new phone, you have not lost the option: sign in with the same Google account, and your contacts, calendar and Google Photos arrive on their own.
iPhone to iPhone
Put the two phones next to each other and turn the new one on. Quick Start appears on the old phone and does the whole job. Choose to transfer directly from iPhone if you are asked, so you do not have to wait for an iCloud download.
Android to iPhone, or iPhone to Android
This is the awkward direction and nothing carries everything.
- Moving to an iPhone, install Apple's Move to iOS app on the Android phone during the iPhone's setup. It brings contacts, messages, photos and some apps.
- Moving to Android, sign in to Google on the new phone for contacts and calendar, install Google Photos on the iPhone first and let it back everything up, then let it come down on the Android.
Before you leave an iPhone, turn off iMessage. Settings, Messages, and switch iMessage off while the SIM is still in. If you skip this, texts from iPhone users will keep going to the old phone and simply never arrive. Fixing it afterwards means a trip to Apple's deregister page.
WhatsApp moves by restoring the backup you made, on the same phone number.
Install WhatsApp on the new phone, verify the same number, and when it offers to restore from Google Drive or iCloud, accept. If you changed platform, Android to iPhone or back, use WhatsApp's own transfer option during setup, because a Google Drive backup cannot be read by an iPhone.
The two things people always lose
- Two-step verification codes. If you use an authenticator app for your bank or your email, move it deliberately. Most have an export or transfer option. If you wipe the old phone first, you can be locked out of your own accounts.
- Photos and videos sent in WhatsApp that were never saved to the gallery. They live only in the chat backup. Restore WhatsApp before you wipe anything.
Last step
Use the new phone for a week before you wipe or sell the old one. Not an hour. A week, so you find the thing you forgot while you can still go back for it.