Here's a list of frequently asked questions about Convert Forms
Does Convert Forms use any cookies?
Yes, it does use the following cookie.
Visitor ID Cookie
A cookie with the name "nrid" is set during pageload and it's mainly used to identify uniquely each visitor. It also helps the extension to tell whether the visitor has seen a particular box.
No personal information such as IP address, User Agent string or the Joomla! User ID is stored in any cookie case.
How can I install it on Joomla! 2.5 or on older versions than Joomla! 3.6?
You can't. Convert Forms supports Joomla 3.6 versions or higher.