How can I find out what version of K2 I have? I am considering the "User Extended Fields for K2" extension which requires ver 2.5.2. Also - when I click on the "DEMO" button for that extenstion it goes to "404 Item Not Found" page - I'm new to K2 would very much like to see the Demo.

In joomla admin go to Extensions - Extension Manager then click on then click the Manage Tab , find K2 in the list the version number is in the 5th column.