Upgrading is quite easy:

vBulletin 3.0.x:
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* overwrite all(!!) PHP-Files from /upload-Folder in your Forum
* run the installer.php in your forum's root and delete it afterwards
* verify if all code-adaptions from the actual installation-instructions are done to your forum/files
* you're done


vBulletin 3.5.x, 3.6.x, 3.7.x and 3.8.x:
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* overwrite all(!!) PHP-Files from /upload-Folder in your Forum
* Update the Product "ibProArcade" in Product-Manager (set "overwrite" to YES to update it)
* you're done


vBulletin 4.x:
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* overwrite all(!!) PHP-Files from /upload-Folder in your Forum
* Update the Product "ibProArcade" in Product-Manager (set "overwrite" to YES to update it)
* read the HTML-installation-instructions-file to do template-adaptions to postbit, postbit_legacy and navbar (for vB4.x)
* you're done
