No, it won't wipe out your existing site...that's why it's taking longer to release (and translations).
Unless you have issues with the year defaults bug you don't need to upgrade. Or, you could..this is how you can upgrade only what is needed to deal with the year defaults bug:
1 - download the new files, unzip them on your hard drive
2 - find the file located at /ndxz-studio/lib/organize.php
3 - upload/replace this file on your website
4 - find the file locationed at /ndxz-studio/site/plugin/index.php
5 - upload/replace this file on your website
These files do not upgrade the language parts...only deal with the year default bug.
Be sure you always back up your site files BEFORE you upgrade...just in case something goes wrong.