To upgrade from any previous 4.0.x release, follow the steps in your website's http://mybaseurl/upgrader.php script. You will need to copy the URL of the attached TAR file as one of these steps ("3: Upload an upgrade TAR for extraction").
» alternatively (but not recommended), you can manually upload the files inside the attached TAR file over existing files (7-zip is just one of many tools for tar files). This is not recommended because it will bypass the upgraders addon-aware extraction algorithm and potentially cause problems.
If you don't follow our advice by taking and testing a backup, and end up needing emergency repair help, ocProducts can help charged at our hourly rate.
For more details, see our upgrading tutorial.
Fixes have been made to a large number of issues. In addition:
- A MyBB forum importer has been added
- A number of usability improvements have been made, including a new emoticon/avatar selection interface
- A new 'startup hooks' facility has been added for developers