Look on the site for the KDE build for the latest version. Cinnamon changed, so the point version change. KDE has not changed, nor has the base Mint changed.
Version dates are usually posted in the Mint blog.
When you install even the very latest .ISO file, you will probably have to update some files to get their latest unless you get an .ISO file immediately after a release. .ISO files are not updated every time a package in the file is updated. Take a look at Debian, they are only at version 6.06 for the stable branch, even though Squeeze was released February 6, 2011. 6.06 was released on September 29, 2012, 4 months ago. Even Ubuntu 12.04 is at 12.04.1, but released last August, that .ISO file would require updates to be installed either during or soon after installation.
If you want an .ISO file with all of the latest updates, look into generating a remastersys
file ( http://remastersys.com/
) which can also contain any personalization which you have done to your installation.