This update method will remove most existing files and then put the new ones in place.
Make a backup of the original files
Make a backup of the database
Download the phpBB 3.3 Full Package archive
Extract the contents of the archive to your computer and open the
Delete the following files from the package:
On your website, delete all files from your board EXCEPT for:
Upload the contents of the
phpBB3directory from your computer to your forum's directory. You may be prompted to overwrite the remaining files. If prompted to merge or overwrite directories, choose to merge them.
docs/folder is for your personal use and it is not necessary to upload it to your forum.
Update the database:
For large boards, you may wish to update via the command line instead of using a web browser. From your board's root, execute the following command:
php ./bin/phpbbcli.php db:migrate --safe-mode
Using your web browser, visit /install/app.php/update in your board's root (e.g. http://www.example.com/yourforum/install/app.php/update). You will see the following warning message: No valid update directory was found, please make sure you uploaded the relevant files. This is expected and not an error.
Select "Update database only" and click Submit
Wait for the progress bar to reach 100% and for a message indicating that the update has completed
Depending on your previous version this will make a number of database changes. You may receive FAILURES during this procedure. They should not be a cause for concern unless you see an actual ERROR, in which case the script will stop (in this case you should seek help via our forums).
install/directory on the server
Ensure that the root level .htaccess file is included in the upload. Some FTP clients do not show files whose names start with a period and you may need to enable the display of hidden files.
When backing up your files via FTP, ensure that the client is in binary mode. If using Filezilla, ensure that the "transfer files without extensions" setting is set to "binary mode".
For more information, see: Knowledge Base: Transferring attachment files with Filezilla
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