[rsuplido]

This will work on 3.8. Don't upload the XML. Just add the plugin directly using 'Add New Plugin' at the CP.

Product: vbuletin
Hook Location: global_start
Title: Custom Date & Time Formats
Execution Order: 5 - I don't know if this needs to be changed but 5 works fine on mine.
Plugin PHP Code:

PHP Code:

if ($vbulletin->userinfo['userid']) {
    // ############ Date Format as Uservalue ################
    switch ($vbulletin->userinfo['field7']) {
     case 'US Format':
        $vbulletin->options['dateformat'] = 'm-d-y';
        break;
     case 'Expanded US Format':
        $vbulletin->options['dateformat'] = 'M jS, Y';
        break;
     case 'European Format':
        $vbulletin->options['dateformat'] = 'd-m-y';
        break;
     case 'Expanded European Format':
        $vbulletin->options['dateformat'] = 'jS M Y';
        break;
     default:
        $vbulletin->options['dateformat'] = 'm-d-y';
    }

    // ############ Time Format as Uservalue ################
    switch ($vbulletin->userinfo['field8']) {
     case '12-Hour Time Format':
        $vbulletin->options['timeformat'] = 'h:i A';
        break;
     case '24-Hour Time Format':
        $vbulletin->options['timeformat'] = 'H:i';
        break;
     default:
        $vbulletin->options['timeformat'] = 'h:i A';
    }
} 


Note that you still need to create the two user fields specified in the .txt file and change the 'fieldx' fields (I'm using field7 and field8 on mine) on the PHP Code (above) corresponding to the two field id's you have created.

Hope this helps.