1. Download  from the client center :
https://secure.visionhelpdesk.com/clientarea.php
2. Copy the PHP 5.3 package as vision.zip and copy PHP 5.2 package to packages/vision_php52.zip and PHP 5.4 package as packages/vision_php54.zip (package should be ground zero zip)
(Not required anymore since there is only one zip available and i.e for PHP 7.1, from version 5.x.x)
3. (At the moment languages is disabled) To enable language we have changed "is_enabled" in avis_language table from 0 to 1 for all languages.
4. Always check upgrade.php to change version
5. Language is not supported in 4.0.2 so we have removed it. Please add it back once developer adds language packs.
6. vision_php52.zip , vision_php54.zip , vision_php55.zip , vision_php56.zip are Removed because they are  removed from Download link.
7. Zend Guard Loader is no more needed by the script(since version 5.x.x), so we have removed it from info.xml :
https://www.visionhelpdesk.com/vision-helpdesks-v5-version-is-now-live.html
8. PHP REQUIREMENT LINK: https://support.visionhelpdesk.com/index.php?/selfhelp/view-article/vision-helpdesk-server-requirements