User summary:
The January 28th playtest package adds the barbarian class for the first time, as well as updating some of the other Classes and Spells. There are also conversion notes for the "Against the Cult of Chaos" season of D&D Encounters.
This playtest packet included:
Playtest Packet (2013-01-28)
D&D Next Playtest Update ("Read First", 3 pages)
How to Play (24 pages)
Creating a Character (5 pages)
Classes (32 pages)
Races (8 pages)
Backgrounds and Skills (11 pages)
Specialties and Feats (11 pages)
Maneuvers (4 pages)
Spells (35 pages)
Equipment (11 pages)
Magic Items (30 pages)
DM Guidelines (14 pages)
Bestiary (95 pages)
Reclaiming Blingdenstone (not updated, 40 pages)
Dungeon Module B2: The Caves of Chaos (not updated, 23 pages)
Dungeon Adventure X1: The Isle of Dread (not updated, 44 pages)
Conversion Notes: Against the Cult of Chaos (19 pages)
The Mud Sorcerer's Tomb (34 pages)
Character sheet (not updated, 2 pages)
Pre-gen: Dwarf Fighter (2 pages)
Pre-gen: Elf Wizard (2 pages)
Pre-gen: Halfling Rogue (2 pages)
Pre-gen: Human Cleric (2 pages)
Pre-gen: Human Fighter (1 page)