Version for older Joomla

[fildin]

Hi guys,
it seems to be like cool extension. I am running a huge magazin with an extensive forum and I would like to use the Author list. There is one "but" ... The website is built on Joomla 1.5 and I don't want to upgrade it due to the high count of modules, plugins and component installed. Is there any possibility to use it for my case?? Thank you for any re.