Minecraft wiki entry for Better_Together_Update, associated text: 1.2.1, 1.2.2 and 1.2.3 fixed numerous bugs.
1.2.5 added the ability to broadcast to Mixer and other streaming services.
1.2.6 saw Realms being integrated with Xbox Live Clubs, and updated textures for horses, mules, and donkeys.
1.2.6.1 was released exclusively on Android to fix numerous bugs.
1.2.7 fixed even more bugs.
1.2.8 fixed a lone bug with the user interface on partnered servers.
1.2.9, 1.2.10 and 1.2.11 fixed even more bugs.
1.2.13 added menu screen transitions, more control options; added many Update Aquatic features as Experimental Gameplay, and fixed even more bugs.
1.2.14 was released exclusively on iOS to disable test commands.
1.2.15 was released exclusively on iOS to fix even more bugs.
1.2.16 (released as 1.2.13.60 on devices other than iOS) fixed even more bugs.