Download PTR Clients
The public test realm (or PTR) is where all of the new features and changes are deployed and tested before they are added to the live game. Nothing you do on the PTR has any affect whatsoever on the live game, and your account and character data might be broken, outdated, or even missing entirely!
These clients work completely separately from the live game clients so it is safe to install the PTR android client along side the live client. It will appear as a separate app with a different icon, and everything (even your preferences) is kept completely separately so there is no danger of accidentally deleting the live client or messing anything up.
It is normal for the PTR to have specific testing goals in mind, check the news “PTR” category for information on what is currently the stuff to test 🙂