1. backup data&db
2. Uploading
On your computer, unzip the file that you downloaded in step 1. Within it, you will see an upload directory. You will be uploading the contents of this directory to your server (not the directory itself).
Connect to your server using your FTP client and navigate to your XenForo root directory (the directory you installed XenForo into). In this directory, you should see files such as admin.php and css.php.
Use your FTP client to upload the
contents of the upload directory that was contained within the zip that you extracted earlier to the XenForo root directory on the server. Ensure that all files and sub-directories are uploaded. If done correctly, you will be overwriting a number of existing files; you should allow your FTP client to do this if it prompts you.
Note
When uploading files, it's very important that you "merge" files with what's on the server. Some FTP clients may simply replace the contents on the server with exactly the contents that you're uploading. If this happens, some files and data may be lost.
This upload may take some time. Once the upload is complete, you must continue with the next step. Your site will be closed until this step is complete.
3. Upgrading
Direct your browser to the install directory under your XenForo root URL. For example, if your XenForo root URL was
www.example.com/community/, you would direct your browser to
www.example.com/community/install/. If you have the correct URL, you should see the XenForo installer.
You may be prompted to login with an administrator user name and password. From there, follow the on-screen instructions to complete the upgrade. Once complete, your site will automatically reopen.