According to a recent tweet by MCPE & PocketMine developer Shoghi Cervantes, we’ll be seeing the beta testing group for 0.12.0 very shortly- even within this week.
We will announce how to join the beta testing later this week. Any groups that are not announced by us are fake, no need to ask.
— Shoghi Cervantes (@shoghicp) July 15, 2015
Mojang’s been running the MCPE beta system since 0.8.0, which they use to help them discover and fix new bugs before they release an update to the public. Betas are always full of bugs, but they’re a great way to access the new features before anyone else.
To join the beta program, you’ll need an Android device to run it on, and a Google Plus account to join the community.