
Note that when playing with this option enabled you can still earn achievements, and Minecraft will create a copy of your world prefixed with EX. To enable go to Game Settings, and turn on Use Experimental Gameplay (beware, you currently can't turn it off again). This is an option in-game which allows for the Player to play with experimental features included in the current update. Related to the Update Aquatic, Mojang introduced the Experimental Gameplay. Everything not included, is likely to be re-introduced in a later beta release and eventually make it into another full release later on. When Minecraft Studio wants to publish the full release, they're going to evaluate which of the various fixes, features, changes and so on they want to implement in that full release. This means that the betas of a given update are releases of the current main development branch, and it doesn't necessarily reflect what is actually going to be included in the full release.

However, as of Update 1.2.10 and the betas related to Update 1.2.13, Minecraft Studios has opted for an alternate concept more resembling the snapshots of Minecraft (Java edition). This is also the normal way to use beta versions. In other words, anything added to a beta version were going to be added in the full release.



The following quote accompanies the newer changelogs from Mojang:
