I've clicked on the OK button when told there is an update for Key available, but nothing happens. I've tried it several times.
Please refer to this article and click on the link "Download the upgrade here." to upgrade to version 2.0.
Thanks for that, Ben. Unfortunately, the link "Download the upgrade here" on that page doesn't appear to be a link, just an image.
The article doesn't indeed contain an active link but should reflect the message you receive when opening Key version 1.X on your desktop.
Please proceed to click on the "Download the upgrade here" visible when you open your current version of KEY.