On the old phone
- Note the exact GB WhatsApp Pro version in Settings → About.
- Run a backup and wait for a timestamp. A spinner is not a finished file.
- Copy that backup to a computer or a storage card you control. Do not post the database in a public link.
Samsung Smart Switch, Xiaomi movers, and similar tools often skip the encrypted chat database. Use them for photos if you want. Still make the in-app backup. The place that backup is written is covered in where GB WhatsApp stores a local chat backup.
On the new phone
Check the new phone’s Android version can run the same build before you wipe the old phone. Put the backup on internal storage, install the same GB line, then verify the number. Accept restore if it is offered during setup. If the old phone used a removable SD card for media, insert that card before the first open, or the paths will point at a drive that is not there.
If chats are missing after setup, do not verify again in a loop. Copy the backup file back into place and reinstall once. The prompt you should see is explained in restoring chats onto the new phone from that backup.
What does not come across
Themes, a chat lock PIN, and some GB-only switches often reset. A new phone number is a new registration, not a transfer. Dual-SIM phones should verify the same SIM you used before, or the backup will not match the account.