2010 and 2011 TVs with a C or D in the model code. Samsung’s support page will help you find your TV’s code. Note that the loss of Netflix support only applies to the TVs themselves; You can still watch Netflix on older Samsung TVs as long as you do so through a device that Netflix currently supports.
It’s possible that more devices will be impacted by the change. Be sure to check Netflix’s official list of supported devices in case you need to find a replacement.