Note that it is imperative to keep your software upgraded to the latest version for security purposes, as well as in order to use the new features available with the new releases.
As mentioned previously you can check your MyBB version via the administrator backend and determine whether there is a new release. You can also check the MyBB official web site for more information about the released versions.
Please note that you need to be running MyBB version RC2 or above in order to successfully accomplish the upgrade.
Here are detailed instructions how to accomplish the upgrade:
Step 1. Download the latest MyBB version.
Step 2. Put your forum offline in order to ensure the upgrade process will not be interrupted. You can do this via Admin CP -> Configuration -> Settings -> Board Online / Offline and change the "Board Closed" option to "Yes"
Step 3. Deactivate all Plugins. This is a necessary step as there is a possibility that a plugin is not compatible with the new version.
Step 4. Backup your web site files and database.
Step 5. Upload all of the files and folders in the "Upload" folder. You should overwrite the existing files and folders for your old MyBB installation.
Note that for major version upgrades (such as 1.2.x to 1.4.x) you will need to find updated versions of any additional non-English language packs you are using. It is recommended that you either upload new versions of the language packs, or remove the existing packs from the server.
Step 6. Change permissions for the following files and directories to 755 (this should not be a necessary step and the permissions should be set properly by default):
- inc/languages (1.2 and later)
- admin/backups (1.2 and later)
- cache (1.4 and later)
- cache/themes (1.4 and later)
Step 7. Access via your web browser:
Where yourdomain.com is your actual domain name and forumfolder is the folder where your forum is installed.
You will see a drop down list asking what version of MyBB you're upgrading from. It is imperative to select the correct version.
Step 8. Run the upgrade script, following all instructions carefully. The process is automatic and you should not experience any troubles.
Step 9. After the upgrade is complete, check that a file called "lock" has been created in the install folder. If it is missing, create it yourself or delete the "install" folder from your server. For extra protection you can change the permissions for inc/config.php to 644.
Step 10. You can now put your forum in online status again.