New Theme releases - Our Denali and Madison themes can be downloaded from your UD Account - https://www.usabilitydynamics.com/account
At the moment these are the available themes: Denali 4.0.2 and Madison 2.0.5
You will need to update them manually(Download from UD Account and upload to your site). There is a slight change in a method, that is the reason why notifications about new releases of themes will be only available after you will have Denali 4.*.* or Madison 2.*.* , so after you will update your theme manually(you will need to do this only once), you will start seeing notifications about new releases again.