There are two ways in which you can achieve this:
1) Login to www.rsjoomla.com. Go to "View my downloads" area and download the com_rsseo.zip file. After you have done this just open your Joomla administrator panel, go to Extensions > Install/Uninstall, browse the previous downloaded file and click Upload and Install.
2) Open your Joomla! administrator panel. Go to Components > RSSeo! > Updates. You will receive a message with a download link. Click to download and save the update. After you have done this just open your Joomla administrator panel, go to Extensions > Install/Uninstall, browse the previous downloaded file and click Upload and Install
This will only update your current RSSeo! installation, it will NOT erase your current RSSeo! data.





