Anyone upgrading from 3.5 can simply replace the whos_online.php in admin and copy the languages files over.

v3.5.3
Fixed the checkbox issue for both IE and Firefox/Opera
Formatted a the options into a table
Added a new option to see last refresh time in AM/PM or 24hour
Added some hyperlinks into the user fields
Added a hidden field for the oscAdminId
Changed all references to HTTP_GET_VARS to $_GET

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