In this documentation, we can check how to backup and restore database in phpBB.
1) Login to phpBB admin panel.
2) Go to ‘Maintenance’.
3) Click the option ‘Backup’.
4) Select the backup options and click ‘Submit’ button.
5) Once the backup has been created, you will get the message that ‘the backup file has been created successfully’.
6) To restore the backup, click the option ‘Restore’.
7) Select the backup file and click the button ‘Start restore’.
That is how we can backup and restore database in phpBB.
If you need any further help please reach our support department.