NVIDIA debuts SHIELD Preview Program to grant users early access to upcoming updates1
A new SHIELD Preview Program is now available for users who own this type of devices. Those who decide to enroll in the program will receive early access to features and improvements on their SHIELD. Moreover, they will gain access to beta forums where they can provide their feedback.
It's worth pointing out that those who own multiple SHIELD devices will have to sign up for an account for each device separately. Before attempting to enroll into the beta program, make sure you have a NVIDIA account.
Either you have a SHIELD tablet or TV, you should start seeing beta updates being delivered to your device as soon as your beta program account is enabled. A fair warning though, you won't be allowed to post any information about these updates outside the beta forums.