Hi,
There is a possibility now to upgrade JoomSEF 3.0.2 to the newest version that doesn't need legacy mode in order to run. Please, backup your site before proceeding with the following steps, in case anything would go wrong!
1. Download the package attached and extract it somewhere on your server.
Attachment upgrade.zip not found
2. Use the extracted upgrade.php file to replace the original one located in /administrator/components/com_sef/installer directory.
3. Use the Upgrade function on JoomSEF's control panel toolbar to automatically upgrade your JoomSEF to the newest available version.
Hope you all enjoy native JoomSEF 3.1 and you won't encounter any problem with the upgrade.
Best regards,
ARTIO Support Team