If you would like to be told when new releases of PuTTY come out, you can subscribe to the PuTTY-announce mailing list.
Please do not send mail to PuTTY-announce! It is not a discussion list. It is not a place to report bugs to. It is a list of people who want to receive one e-mail, from the PuTTY developers, every time there is a new release. All posts from other people, even list members, will be rejected. Bugs and comments should be sent to putty-bugs@lists.tartarus.org.
The mailing list information page is here.