Kartris 2.0 and onwards are licensed by default with the GNU
General Public License v2 (normally abbreviated to GPL v2). This is a
free open-source license. Please read the license terms carefully - in
particular, the license requires you to ensure that you do not remove
code that displays copyright and warranty information to users. So the
'powered by' link at the foot of pages must be retained under this
license.
This license permits removal of the 'powered by' link from
Kartris sites for the domain or subdomain for which it is purchased.
There is no expiry date on the license, so you can use this with
future Kartris releases - once your domain is licensed, you can
upgrade to a newer Kartris version and continue to use this
license.