The upgrade procedure requires that you overwrite the old b2evolution files with the new files from the new release (and after that you should run the install/upgrade script).

If you are unsure where to upload the new files, here’s what you should do:

1. First connect to your b2evolution backoffice/admin interface. Notice the version number at the bottom of every admin page.
2. Then, using your FTP software, try to locate the file called admin.php on your server.
3. Now, try to rename this file, for example to admin2.php.
4. Try refreshing the page you opened in step 1. You should get a 404 error because the admin script is no longer present. If, on the contrary, you are still able to connect and use your backoffice, it means you haven’t found and renamed the right file in the right location.
5. Once you have found the correct admin.php file, you are in the folder that matches your $baseurl. (Rename the file back to admin.php).
6. You can now upload all the files from the b2evolution distribution ZIP file in this location. When you upload the files, the new admin.php should replace the old one. And all other files from the distribution (including in subdirectories) should also replaced your old files.
7. After the upload, trying to connect to your backoffice (reloading the admin page from step 1) should either tell you that you need to upgrade the database now (by calling the install/upgrade script) or it should show a new version number at the bottom of the page. If neither of this happens, it means you have not uploaded your files in the proper location.