Spry Fox has gone live with a beta sign-up for anyone who has the Google Play version of Triple Town should they be interested in checking out new features and testing them before they get released to the rest of the public to enjoy. The beta requires you to have the Google Play version of the game and will not work with the Amazon AppStore version.
Having the Google Play version of Triple Town is pretty much the only requirement needed to qualify as a beta tester for upcoming features to the game. Joining the group won't just give you access to upcoming features to test but also bug fixes and 'other goodness' before the public does in an official update.
Since this is beta testing, new features being worked on could also bring with them new bugs as well, so if you don't like testing games and dealing with bugs, don't bother signing up. However, if you're up for it, head on over to the official beta sign-up forum which is linked below and join the beta testing group on Google (just click the join group button).