From Minecraft Wiki
July 26, 2012
1.3-pre is the first pre-release for 1.3.1.
- The block-breaking animation is now shown in F1 mode
- TNT no longer does damage to players in peaceful difficulty
- Respawning in superflat is no longer random
5 bugs fixed
- Fixed a few misalignments and oddities in the item spritesheet and the creative mode's inventory's graphics.
- Fixed a crash bug.
- Fixed the chest armor slot being inaccessible in Creative mode's survival inventory tab.
- Fixed rotated wooden logs mined using Silk Touch enchanted tools dropping as rotated wooden logs.
- Fixed being unable to place half slabs in the small gaps between another half slab and the side of another block.